This document summarizes a study of three interchange designs: contraflow left interchange, displaced left interchange, and modified single point interchange. It describes the key aspects of each design such as typical roadway geometry, traffic operations, applicable locations, and pros and cons. It also presents the results of traffic analysis software (Synchro) to determine the level of service for each interchange. The goal of the study is to evaluate these interchange designs and identify measures to improve safety and reduce delays.
Roundabouts provide environmental, economic, and safety benefits over traditional intersections. They reduce greenhouse gas emissions by decreasing idling time and promoting continuous traffic flow. Construction and maintenance costs are often lower for roundabouts which do not require traffic signals or expensive infrastructure. Multiple studies show roundabouts reduce collisions and injuries at intersections by up to 90% by lowering speeds and eliminating high-risk collision angles. Washington state is promoting roundabouts as part of its strategy to reduce transportation emissions and meet sustainability goals.
The document discusses road networks and their classification. It describes the different types of roads that make up a road network hierarchy, from freeways that provide largely uninterrupted travel at high speeds, to arterial roads that deliver traffic to freeways, to collector roads that move traffic from local streets to arterials, to local roads with the lowest speeds that provide access to properties. Maintaining accurate and up-to-date road network data is challenging using traditional record keeping methods, so the document advocates using a geographic information system to facilitate planning, implementation, and decision making for road sector management.
TRAFFIC FLOW ANALYSIS & EFFICIENCY OF GEOMETRIC DESIGN OF A T-INTERSECTION, A...IAEME Publication
The major concern for a Highway Engineer in any road network system is an intersection.The heterogeneous traffic is more diverse in nature due to lane changing and lack of lane discipline characteristics of drivers’ in India. Our research is intended to check the efficiency and control of flow of traffic at “Tara Wala Pul (Bridge)-T intersection” , point out flaws (if any) in the geometric design and work out the possible solutions.
Lec 07 Intersection Design (Transportation Engineering Dr.Lina Shbeeb)Hossam Shafiq I
This document discusses different types of intersections and how they are designed. There are three main categories of intersections: grade separated without ramps, grade separated with ramps, and at-grade. At-grade intersections are further broken down into T-intersections, four-leg intersections, and multi-leg intersections with five or more approaches. Proper channelization of intersections is important to increase capacity and safety by separating conflicting traffic movements. Traffic islands can be used to control and direct traffic, divide opposing flows, or provide pedestrian refuge.
Traffic demand management aims to reduce single-occupancy vehicle travel and redistribute travel demand. Managing traffic demand at junctions is important to reduce accidents, pollution, wasted time and money, and improve public transportation options. Several methods can be used for traffic demand management at junctions, including traffic surveys, educating the public, enforcing traffic laws, improving junction infrastructure with signs, flyovers, traffic lights, and pedestrian crossings, implementing bicycle infrastructure, congestion pricing, active traffic management, and integrated demand management. Case studies demonstrate how these strategies can be applied using existing traffic control systems.
This document discusses junction design and traffic engineering. It defines different types of junctions including intersections and interchanges. Factors that affect junction loads are discussed. The types of movements at junctions like turning, merging, and diverging are also outlined. Conflict points and areas at intersections are explained. Methods to reduce conflicts at four-leg junctions using techniques like channelization are presented. Selection factors for junction types and different types of sight distances at junctions are also summarized. Finally, traffic light design and terminology used in traffic light phasing are covered.
This document discusses different types of road intersections and design considerations. It describes two main types of intersections - grade-separated, which use overpasses or underpasses to eliminate conflicts, and at-grade intersections. Some key intersection types are described, including diamond, cloverleaf, and directional interchanges. Design elements like capacity, traffic control, and accommodation of pedestrians and bicycles are also covered. The objective of grade-separated intersections is to eliminate conflicts while accommodating turning movements. Channelization is discussed as a way to reduce the conflict area at intersections.
A case study on Rajkillpakkam Junction,ChennaiSukhdeep Jat
My project work is a case study on Rajkillpakkam Junction, Chennai.....in this project you can find the manual method of designing a traffic junction in an efficient output.
Roundabouts provide environmental, economic, and safety benefits over traditional intersections. They reduce greenhouse gas emissions by decreasing idling time and promoting continuous traffic flow. Construction and maintenance costs are often lower for roundabouts which do not require traffic signals or expensive infrastructure. Multiple studies show roundabouts reduce collisions and injuries at intersections by up to 90% by lowering speeds and eliminating high-risk collision angles. Washington state is promoting roundabouts as part of its strategy to reduce transportation emissions and meet sustainability goals.
The document discusses road networks and their classification. It describes the different types of roads that make up a road network hierarchy, from freeways that provide largely uninterrupted travel at high speeds, to arterial roads that deliver traffic to freeways, to collector roads that move traffic from local streets to arterials, to local roads with the lowest speeds that provide access to properties. Maintaining accurate and up-to-date road network data is challenging using traditional record keeping methods, so the document advocates using a geographic information system to facilitate planning, implementation, and decision making for road sector management.
TRAFFIC FLOW ANALYSIS & EFFICIENCY OF GEOMETRIC DESIGN OF A T-INTERSECTION, A...IAEME Publication
The major concern for a Highway Engineer in any road network system is an intersection.The heterogeneous traffic is more diverse in nature due to lane changing and lack of lane discipline characteristics of drivers’ in India. Our research is intended to check the efficiency and control of flow of traffic at “Tara Wala Pul (Bridge)-T intersection” , point out flaws (if any) in the geometric design and work out the possible solutions.
Lec 07 Intersection Design (Transportation Engineering Dr.Lina Shbeeb)Hossam Shafiq I
This document discusses different types of intersections and how they are designed. There are three main categories of intersections: grade separated without ramps, grade separated with ramps, and at-grade. At-grade intersections are further broken down into T-intersections, four-leg intersections, and multi-leg intersections with five or more approaches. Proper channelization of intersections is important to increase capacity and safety by separating conflicting traffic movements. Traffic islands can be used to control and direct traffic, divide opposing flows, or provide pedestrian refuge.
Traffic demand management aims to reduce single-occupancy vehicle travel and redistribute travel demand. Managing traffic demand at junctions is important to reduce accidents, pollution, wasted time and money, and improve public transportation options. Several methods can be used for traffic demand management at junctions, including traffic surveys, educating the public, enforcing traffic laws, improving junction infrastructure with signs, flyovers, traffic lights, and pedestrian crossings, implementing bicycle infrastructure, congestion pricing, active traffic management, and integrated demand management. Case studies demonstrate how these strategies can be applied using existing traffic control systems.
This document discusses junction design and traffic engineering. It defines different types of junctions including intersections and interchanges. Factors that affect junction loads are discussed. The types of movements at junctions like turning, merging, and diverging are also outlined. Conflict points and areas at intersections are explained. Methods to reduce conflicts at four-leg junctions using techniques like channelization are presented. Selection factors for junction types and different types of sight distances at junctions are also summarized. Finally, traffic light design and terminology used in traffic light phasing are covered.
This document discusses different types of road intersections and design considerations. It describes two main types of intersections - grade-separated, which use overpasses or underpasses to eliminate conflicts, and at-grade intersections. Some key intersection types are described, including diamond, cloverleaf, and directional interchanges. Design elements like capacity, traffic control, and accommodation of pedestrians and bicycles are also covered. The objective of grade-separated intersections is to eliminate conflicts while accommodating turning movements. Channelization is discussed as a way to reduce the conflict area at intersections.
A case study on Rajkillpakkam Junction,ChennaiSukhdeep Jat
My project work is a case study on Rajkillpakkam Junction, Chennai.....in this project you can find the manual method of designing a traffic junction in an efficient output.
Intersection CONCEPTUAL DESIGN Methodology, by Grant Johnson PE PTOEGrant Johnson, PE
It starts with analysis. Synchro Pro. Then a common sense approach to building an intersection design that follows analysis. First learn the traffic patterns, and then maximize flow rates and capacity by designing smart. Not smart growth, but smart design based on common sense and putting resources like lanes and signal timing where it is most needed, eliminating waste in design. True problem solving.
Intersections present safety risks because different road users must share the same space. They are locations of up to 50% of urban crashes and 10-20% of rural crashes. The main principles to consider for intersection safety are reducing speeds, separating conflicts in space and time, and providing clear right-of-way rules. Common intersection controls include signs, roundabouts, and traffic signals. Roundabouts are often the safest option as they reduce conflict points and speeds. Traffic engineering can greatly improve intersection safety through proper sight distances, control types, and road design.
Identification of vehicular growth and its management on nh 202 in ranga redd...EditorIJAERD
This document summarizes a study on identifying vehicular growth and its management on NH-202 in Ranga Reddy District, India. Detailed traffic surveys were conducted on NH-202 and other major roads to assess baseline traffic characteristics. The surveys found high volumes of goods and passenger vehicles. The objectives of the study were to determine existing vehicular growth, pavement conditions for widening the single lane to double lane, equivalent single axle loads, and material selection and reuse for pavement construction. Traffic data analysis provided inputs for highway design, junction design, pavement design, and environmental impact assessment to manage the identified vehicular growth on NH-202.
at-grade junction where two or more roads or streets meet or cross.
THIS AREA IS DESIGNATED FOR THE VEHICLES TO TURN TO Different Direction.
VEHICLES MOVING IN DIFFERENT DIRECTION WANT TO OCCUPY SAME SPACE AT SAME TIME.
This document discusses the advantages of using roundabouts for traffic control from the perspective of Williams and Associates, an engineering firm based in Athens, Georgia. It outlines 7 key advantages of modern roundabouts: 1) safety, as they reduce conflict points and severity of accidents; 2) functional performance, as traffic flow is improved with continuous movement; 3) economic benefits from reduced maintenance costs and accidents; 4) environmental benefits from less idling and emissions; 5) traffic calming effects from lower design speeds; 6) aesthetic benefits from landscaping opportunities; and 7) improved pedestrian safety and access from lower vehicle speeds. The document provides an overview of roundabouts and their traffic control functions.
(3.4.1.2)station design guidelines final 122309Avtansh Ghai
The document provides guidelines for station design along the South Florida East Coast Corridor transit project. It discusses the project location, goals of integrating transit into communities and providing a sustainable system. It also establishes eight station typologies and identifies five transit modes to be studied. The guidelines are intended to standardize components while allowing for local identity. It provides recommendations over eight chapters for all aspects of station planning, design, and maintenance to achieve an efficient and coordinated system along the 85-mile corridor.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
IRJET- Traffic Study on Mid-Block Section & IntersectionIRJET Journal
This document summarizes a study on traffic patterns at mid-block sections and intersections in Borawan, India. Traffic volume data was collected over four days at five locations experiencing heavy traffic issues, including post office chouraha and gaaytri mandir tiraha. Both manual and automatic counting methods were used to collect data on vehicle types at different times of day. The results show peak traffic volumes during morning and evening rush hours. The study aims to improve traffic conditions and reduce accidents by examining the current levels of service and making recommendations for infrastructure improvements like expanding road dimensions or constructing flyovers. A literature review discusses previous research on pedestrian and vehicle behavior at crosswalks, and the impact of mid-block crosswalks on traffic
This document summarizes an undergraduate thesis project that proposed an alternative transportation plan for Clemson, South Carolina to promote walking, biking, and public transportation over driving. The plan involved creating concentric zones with different transportation emphases - a bike and pedestrian core would be surrounded by a bus emphasis zone and then a car emphasis zone. Within the core, a connected bike and pedestrian network was proposed. The project included extensive research like surveys, mapping, and case studies to support the argument and guide the design. The goals were to provide more transportation options, reduce costs, stimulate the economy, and create a healthier community.
The document summarizes information presented in a WisDOT webinar on reduced conflict intersection designs. It discusses the Intersection Design and Operations Task Force, which aims to disseminate information on emerging intersection concepts. It provides overviews and considerations for diverging diamond interchanges, J-turn intersections, and references design guidance documents. Intersection designs discussed include reduced conflict points to increase safety compared to traditional designs.
02-B Components of Traffic System [Roadway and Control Device] (Traffic Engin...Hossam Shafiq I
This document discusses components of the traffic system including roadways and control devices. It covers five elements of the traffic system: users, vehicles, roadways, controls, and the general environment. Roadways provide accessibility for direct connection to land uses and mobility for vehicle movement. Control devices communicate traffic laws and regulations to drivers through markings, signs, and signals. The Manual on Uniform Traffic Control Devices (MUTCD) establishes standards for the application and design of control devices.
Road junction design, parking and signal designAkshay Galav
This document provides an introduction to road junction design, parking, and signal design. It discusses the principles of road junction design, including using right angles where possible and avoiding acute intersections. Roundabouts are recommended when more than three roads intersect. Parking is classified as on-street, off-street, or based on operations like parallel, angle, or right-angle. Traffic signals are used to control vehicle movement and include regulatory, warning, informative, and different types of control like fixed time, fully actuated, and semi-actuated signals. Illustrative examples of different junctions and parking lot designs are also included.
This document summarizes a public open house meeting for a transit study between Amherst and Buffalo, New York. It presented the study process, alternatives being considered, and results of screening so far. Light rail transit and bus rapid transit alternatives on Niagara Falls Boulevard and Bailey Avenue were identified to advance to further analysis in the next phase of the study. The meeting provided information on the alternatives and sought public input to help identify a locally preferred alternative for the corridor by fall 2015.
Intersections & Interchanges ( Highway Engineering Dr. Sherif El-Badawy )Hossam Shafiq I
This document discusses different types of intersections and interchanges, including their key elements and design considerations. It describes at-grade intersections, channelization techniques, and different interchange configurations like diamonds, cloverleafs, and trumpets. The document also covers factors in curb radius, turn lane, and sight distance design, and provides examples of determining sufficient sight distance at intersections.
Lec 15 Transit Operations (Transportation Engineering Dr.Lina Shbeeb)Hossam Shafiq I
This document discusses various aspects of transit route planning, including route location, stop location, and scheduling. Some key points covered include:
1. Route location involves decisions about overall network configuration and spacing of routes, with the goal of maximizing access within 0.4 km of passengers.
2. Stop spacing balances walking distances and bus travel time. There should be 3-4 stops per mile with no more than 7-8.
3. Scheduling aims for uniform headways to make the system easier for passengers to use. Headways vary based on demand and operating costs.
This document discusses different types of intersection controls. It describes passive control which involves no explicit control or uses signs. Semi control includes channelization and traffic rotaries to separate traffic flows. Active control uses traffic signals or grade separated intersections to control traffic. Traffic signals separate traffic using time-sharing while grade separated intersections separate traffic vertically using overpasses, underpasses, flyovers and interchanges like diamonds, trumpets and cloverleafs. Channelized intersections also help reduce conflicts.
Effectiveness Analysis of Travel Time For Mode Alternatife Trnasportation Bec...IJERA Editor
The purpose of this research is to obtain a model of user behavior modes of transportation in the city of Semarang in choosing the two modes of transportation, namely Modes A (rickshaw) and Mode B (motorized rickshaws), using the approach of Logit Binomial Model with three variables (cost, time and distance) with method stated preference. From the data processing, which consists of travel time, travel expenses, the distance traveled and the proportion of modal choice between Modes A and Mode B based on the cost of travel, travel time and travel distance, is analyzed with regression analysis, correlation, analysis of variance, multiple linear regression, linear interpolation. In this study of three variables, namely the analysis of costs, time and distance, researchers modeling the behavior of users rickshaws and motorized rickshaws gradually. The first researchers to model the Binomial logit model with two variables: cost and time, then the modeled user behavior mode again with the same analytical model with variable costs and the distance. Both models were then compared with regards variable costs in the first model as a reference to obtain the magnitude of the difference in cost, the time difference and the difference in distance as well.
Virginia Statewide Roundabout Guidance (Transportation Research Board)Andy Boenau
The Virginia Department of Transportation (VDOT) revised its Road Design Manual in 2008 to include a policy statement on roundabouts. The policy says that “[...when a roundabout is feasible] it should be considered the Department’s preferred alternative due to the proven substantial safety and operational benefits.
This is one of the stronger policy statements of any state in the United States. However, it has been difficult for VDOT to consistently implement and adhere to this policy on intersection projects throughout the state without a supporting process and/or tool and appropriate guidance.
Timmons Group and Kittelson & Associates, Inc. were hired to develop a repeatable process and series of tools to quickly and efficiently evaluate roundabouts. The intent was to create a procedure that could be used early in project planning and continue through project design.
Presented by Andy Boenau and Chris Tiesler at the Transportation Research Board's 4th International Conference on Roundabouts.
1) Traffic management techniques include ramp metering, which uses traffic lights to control the flow of vehicles entering highways and maintain steady traffic flow.
2) Physical changes to roads, such as converting two-way streets to one-way streets, road markings, and tidal flow lanes that change direction during peak hours, can improve traffic flow.
3) Providing information through signs helps guide drivers and encourages alternatives to single-occupancy vehicles, such as high-occupancy vehicle lanes that prioritize cars with multiple passengers.
This document outlines the sections and chapters of a homework assignment, listing the section numbers and titles for each part of the first chapter. It includes sections on specific math concepts as well as a chapter review at the end.
Brazil's Mining Tragedy : Lessons for the Mining IndustryPRABHASH GOKARN
The Brazilian mining tragedy of 2015 involved the collapse of two tailings dams at an iron ore mine owned by Samarco Mineração S.A., a joint venture between Vale and BHP Billiton. Over 60 million cubic meters of mining waste and sludge were released, flooding the nearby town of Bento Rodrigues and killing at least 13 people. The toxic waste traveled down the Rio Doce river to the Atlantic Ocean, devastating biodiversity and water sources along the way. The disaster highlighted the need for improved tailings dam design, monitoring, emergency response planning, and regulatory enforcement to prevent such catastrophes in the future.
Intersection CONCEPTUAL DESIGN Methodology, by Grant Johnson PE PTOEGrant Johnson, PE
It starts with analysis. Synchro Pro. Then a common sense approach to building an intersection design that follows analysis. First learn the traffic patterns, and then maximize flow rates and capacity by designing smart. Not smart growth, but smart design based on common sense and putting resources like lanes and signal timing where it is most needed, eliminating waste in design. True problem solving.
Intersections present safety risks because different road users must share the same space. They are locations of up to 50% of urban crashes and 10-20% of rural crashes. The main principles to consider for intersection safety are reducing speeds, separating conflicts in space and time, and providing clear right-of-way rules. Common intersection controls include signs, roundabouts, and traffic signals. Roundabouts are often the safest option as they reduce conflict points and speeds. Traffic engineering can greatly improve intersection safety through proper sight distances, control types, and road design.
Identification of vehicular growth and its management on nh 202 in ranga redd...EditorIJAERD
This document summarizes a study on identifying vehicular growth and its management on NH-202 in Ranga Reddy District, India. Detailed traffic surveys were conducted on NH-202 and other major roads to assess baseline traffic characteristics. The surveys found high volumes of goods and passenger vehicles. The objectives of the study were to determine existing vehicular growth, pavement conditions for widening the single lane to double lane, equivalent single axle loads, and material selection and reuse for pavement construction. Traffic data analysis provided inputs for highway design, junction design, pavement design, and environmental impact assessment to manage the identified vehicular growth on NH-202.
at-grade junction where two or more roads or streets meet or cross.
THIS AREA IS DESIGNATED FOR THE VEHICLES TO TURN TO Different Direction.
VEHICLES MOVING IN DIFFERENT DIRECTION WANT TO OCCUPY SAME SPACE AT SAME TIME.
This document discusses the advantages of using roundabouts for traffic control from the perspective of Williams and Associates, an engineering firm based in Athens, Georgia. It outlines 7 key advantages of modern roundabouts: 1) safety, as they reduce conflict points and severity of accidents; 2) functional performance, as traffic flow is improved with continuous movement; 3) economic benefits from reduced maintenance costs and accidents; 4) environmental benefits from less idling and emissions; 5) traffic calming effects from lower design speeds; 6) aesthetic benefits from landscaping opportunities; and 7) improved pedestrian safety and access from lower vehicle speeds. The document provides an overview of roundabouts and their traffic control functions.
(3.4.1.2)station design guidelines final 122309Avtansh Ghai
The document provides guidelines for station design along the South Florida East Coast Corridor transit project. It discusses the project location, goals of integrating transit into communities and providing a sustainable system. It also establishes eight station typologies and identifies five transit modes to be studied. The guidelines are intended to standardize components while allowing for local identity. It provides recommendations over eight chapters for all aspects of station planning, design, and maintenance to achieve an efficient and coordinated system along the 85-mile corridor.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
IRJET- Traffic Study on Mid-Block Section & IntersectionIRJET Journal
This document summarizes a study on traffic patterns at mid-block sections and intersections in Borawan, India. Traffic volume data was collected over four days at five locations experiencing heavy traffic issues, including post office chouraha and gaaytri mandir tiraha. Both manual and automatic counting methods were used to collect data on vehicle types at different times of day. The results show peak traffic volumes during morning and evening rush hours. The study aims to improve traffic conditions and reduce accidents by examining the current levels of service and making recommendations for infrastructure improvements like expanding road dimensions or constructing flyovers. A literature review discusses previous research on pedestrian and vehicle behavior at crosswalks, and the impact of mid-block crosswalks on traffic
This document summarizes an undergraduate thesis project that proposed an alternative transportation plan for Clemson, South Carolina to promote walking, biking, and public transportation over driving. The plan involved creating concentric zones with different transportation emphases - a bike and pedestrian core would be surrounded by a bus emphasis zone and then a car emphasis zone. Within the core, a connected bike and pedestrian network was proposed. The project included extensive research like surveys, mapping, and case studies to support the argument and guide the design. The goals were to provide more transportation options, reduce costs, stimulate the economy, and create a healthier community.
The document summarizes information presented in a WisDOT webinar on reduced conflict intersection designs. It discusses the Intersection Design and Operations Task Force, which aims to disseminate information on emerging intersection concepts. It provides overviews and considerations for diverging diamond interchanges, J-turn intersections, and references design guidance documents. Intersection designs discussed include reduced conflict points to increase safety compared to traditional designs.
02-B Components of Traffic System [Roadway and Control Device] (Traffic Engin...Hossam Shafiq I
This document discusses components of the traffic system including roadways and control devices. It covers five elements of the traffic system: users, vehicles, roadways, controls, and the general environment. Roadways provide accessibility for direct connection to land uses and mobility for vehicle movement. Control devices communicate traffic laws and regulations to drivers through markings, signs, and signals. The Manual on Uniform Traffic Control Devices (MUTCD) establishes standards for the application and design of control devices.
Road junction design, parking and signal designAkshay Galav
This document provides an introduction to road junction design, parking, and signal design. It discusses the principles of road junction design, including using right angles where possible and avoiding acute intersections. Roundabouts are recommended when more than three roads intersect. Parking is classified as on-street, off-street, or based on operations like parallel, angle, or right-angle. Traffic signals are used to control vehicle movement and include regulatory, warning, informative, and different types of control like fixed time, fully actuated, and semi-actuated signals. Illustrative examples of different junctions and parking lot designs are also included.
This document summarizes a public open house meeting for a transit study between Amherst and Buffalo, New York. It presented the study process, alternatives being considered, and results of screening so far. Light rail transit and bus rapid transit alternatives on Niagara Falls Boulevard and Bailey Avenue were identified to advance to further analysis in the next phase of the study. The meeting provided information on the alternatives and sought public input to help identify a locally preferred alternative for the corridor by fall 2015.
Intersections & Interchanges ( Highway Engineering Dr. Sherif El-Badawy )Hossam Shafiq I
This document discusses different types of intersections and interchanges, including their key elements and design considerations. It describes at-grade intersections, channelization techniques, and different interchange configurations like diamonds, cloverleafs, and trumpets. The document also covers factors in curb radius, turn lane, and sight distance design, and provides examples of determining sufficient sight distance at intersections.
Lec 15 Transit Operations (Transportation Engineering Dr.Lina Shbeeb)Hossam Shafiq I
This document discusses various aspects of transit route planning, including route location, stop location, and scheduling. Some key points covered include:
1. Route location involves decisions about overall network configuration and spacing of routes, with the goal of maximizing access within 0.4 km of passengers.
2. Stop spacing balances walking distances and bus travel time. There should be 3-4 stops per mile with no more than 7-8.
3. Scheduling aims for uniform headways to make the system easier for passengers to use. Headways vary based on demand and operating costs.
This document discusses different types of intersection controls. It describes passive control which involves no explicit control or uses signs. Semi control includes channelization and traffic rotaries to separate traffic flows. Active control uses traffic signals or grade separated intersections to control traffic. Traffic signals separate traffic using time-sharing while grade separated intersections separate traffic vertically using overpasses, underpasses, flyovers and interchanges like diamonds, trumpets and cloverleafs. Channelized intersections also help reduce conflicts.
Effectiveness Analysis of Travel Time For Mode Alternatife Trnasportation Bec...IJERA Editor
The purpose of this research is to obtain a model of user behavior modes of transportation in the city of Semarang in choosing the two modes of transportation, namely Modes A (rickshaw) and Mode B (motorized rickshaws), using the approach of Logit Binomial Model with three variables (cost, time and distance) with method stated preference. From the data processing, which consists of travel time, travel expenses, the distance traveled and the proportion of modal choice between Modes A and Mode B based on the cost of travel, travel time and travel distance, is analyzed with regression analysis, correlation, analysis of variance, multiple linear regression, linear interpolation. In this study of three variables, namely the analysis of costs, time and distance, researchers modeling the behavior of users rickshaws and motorized rickshaws gradually. The first researchers to model the Binomial logit model with two variables: cost and time, then the modeled user behavior mode again with the same analytical model with variable costs and the distance. Both models were then compared with regards variable costs in the first model as a reference to obtain the magnitude of the difference in cost, the time difference and the difference in distance as well.
Virginia Statewide Roundabout Guidance (Transportation Research Board)Andy Boenau
The Virginia Department of Transportation (VDOT) revised its Road Design Manual in 2008 to include a policy statement on roundabouts. The policy says that “[...when a roundabout is feasible] it should be considered the Department’s preferred alternative due to the proven substantial safety and operational benefits.
This is one of the stronger policy statements of any state in the United States. However, it has been difficult for VDOT to consistently implement and adhere to this policy on intersection projects throughout the state without a supporting process and/or tool and appropriate guidance.
Timmons Group and Kittelson & Associates, Inc. were hired to develop a repeatable process and series of tools to quickly and efficiently evaluate roundabouts. The intent was to create a procedure that could be used early in project planning and continue through project design.
Presented by Andy Boenau and Chris Tiesler at the Transportation Research Board's 4th International Conference on Roundabouts.
1) Traffic management techniques include ramp metering, which uses traffic lights to control the flow of vehicles entering highways and maintain steady traffic flow.
2) Physical changes to roads, such as converting two-way streets to one-way streets, road markings, and tidal flow lanes that change direction during peak hours, can improve traffic flow.
3) Providing information through signs helps guide drivers and encourages alternatives to single-occupancy vehicles, such as high-occupancy vehicle lanes that prioritize cars with multiple passengers.
This document outlines the sections and chapters of a homework assignment, listing the section numbers and titles for each part of the first chapter. It includes sections on specific math concepts as well as a chapter review at the end.
Brazil's Mining Tragedy : Lessons for the Mining IndustryPRABHASH GOKARN
The Brazilian mining tragedy of 2015 involved the collapse of two tailings dams at an iron ore mine owned by Samarco Mineração S.A., a joint venture between Vale and BHP Billiton. Over 60 million cubic meters of mining waste and sludge were released, flooding the nearby town of Bento Rodrigues and killing at least 13 people. The toxic waste traveled down the Rio Doce river to the Atlantic Ocean, devastating biodiversity and water sources along the way. The disaster highlighted the need for improved tailings dam design, monitoring, emergency response planning, and regulatory enforcement to prevent such catastrophes in the future.
The document discusses the Syrian crisis and the role of the US. It claims that the US wants a perpetual state of war to benefit weapons manufacturers and bankers. It alleges that groups like Al-Qaeda and ISIS were originally formed with CIA support to fight US proxy wars and have now backfired. The document argues there are currently three wars being fought in Syria between the government and rebels, Saudi Arabia and Iran, and the US and Russia, and that the US policy in the region is driven by interests in oil and supporting Israel.
Akkel Ali Seikh: A forgotten Freedom fighter of East Bengal origin in AssamPurbita Ditecha
Akkel Ali Seikh was a peasant leader in British India who fought for independence and the rights of oppressed groups. He gained popularity among peasants and Bengali Muslims for his selfless support. Seikh participated in the Khilafat Movement and led Muslims in Assam during the 1930 Line System protests. As a member of the Indian National Congress from East Bengal, he joined the Quit India Movement. After partition, Seikh stayed in India while his political mentor left for Pakistan.
Dutch - Linking the supply chain triangle to strategy.Bram Desmet
Article from Value Chain Magazine. In a series of articles inspired by the book Supply Chain Metrics that Matter from Lora Cecere. In this fourth article, we link the supply chain triangle to the strategy model of Treacy & Wiersema. We show the strategy defines the trade-off between EBIT and inventory turns. In a fifth article, we extend that into a benchmark of multiple companies.
The document discusses an Android application to educate people about India's Twelfth Five Year Plan. The application aims to inform users about the key aspects of the Twelfth Five Year Plan. It will provide information on the workings of the Twelfth Five Year Plan in a concise manner through the mobile application.
Improving Water Quality by Constructing an Effluent Treatment PlantPRABHASH GOKARN
This document discusses the construction of an effluent treatment plant (ETP) by Tata Steel at Sukinda, Odisha, India to improve water quality. It describes how mining activities were contaminating local water sources with hexavalent chromium. The ETP uses chemical precipitation technology for fast and efficient treatment. It faces challenges like strict timelines and site constraints but has unique features like achieving output water quality better than standards and state-of-the-art online monitoring. The goal is to move towards zero discharge of treated water.
Changing Profile Of Pig Iron Industry & Lessons For All Industries GokarnPRABHASH GOKARN
The document discusses how the economic downturn has forced changes in the Indian pig iron industry. It led to a need for greater operational efficiency and moving up the value chain through activities like producing specialized pig iron, steel making, and foundry work. Lessons for all industries are to secure raw materials, improve efficiency, and expand into higher value business lines. The pig iron industry specifically faces pressures around raw material security and moving into steel and downstream industries.
Tata Steel has been practicing TQM since the late 1980s, focusing on improving processes, efficiencies, quality, and performance. It established standardized daily management activities and involved employees in improvement activities. Tata Steel transformed into a world-class company through TQM, reducing costs and defects while improving productivity, customer satisfaction, and safety. This led to Tata Steel becoming the first steel company to win the prestigious Deming Application Prize for achieving distinctive performance through TQM.
A study on gap acceptance of unsignalized intersection under mixed traffic co...eSAT Publishing House
This document summarizes a study on analyzing the capacity of unsignalized intersections under mixed traffic conditions in Visakhapatnam, India using the conflict technique method. Traffic data was collected through manual counts at three intersections to determine traffic volumes, flows, and capacities. The modified Tanner's formula capacity model was found to be most suitable. Tables and figures show the results of the traffic data collection, including the maximum number of vehicles and capacities for different turning movements at each intersection during morning and evening peak hours. The conclusions indicate the conflict technique is a simple method for this analysis and the modified Tanner's formula provided the best model.
Design of traffic signal on NH-12 near Barkatullah University, Bhopal Distric...IRJET Journal
This document summarizes a study on designing traffic signals on NH-12 near Barkatullah University in Bhopal, India. It begins with an abstract describing the growth of traffic in major towns due to industrialization and urbanization. The objectives of the study are to minimize delays at intersections, improve traffic flow, and enhance the level of service. Existing traffic volumes were measured using manual counts, and signals were designed using the Webster and two-phase signal methods. Key findings include calculated passenger car units per hour, saturation flow rates for different lane widths, and cycle times determined using the Webster method to minimize total vehicle delay. The study methodology involved manual traffic counts, conversion to passenger car units, and signal design using two-phase
A Review on Optimization of Design and Safety of IntersectionIRJET Journal
1. The document reviews optimization of design and safety at intersections. It discusses reducing conflict points, congestion, and delay.
2. Intersection design factors like entry/exit radii, sight distances, and channelized islands are examined. Proper widening, marking, and signaling can minimize conflicts and efficiently flow traffic.
3. Sources of delay at intersections include traffic growth, lane indiscipline, and heterogeneous traffic characteristics in developing countries. Models for estimating saturation flow from other countries may not apply due to differences in traffic behaviors.
4. Conflicting traffic maneuvers at intersections make them prone to crashes. Understanding the interactions between geometric designs, traffic flows, and crashes can help identify effective safety countermeasures.
This traffic impact assessment document discusses how a proposed development project will affect existing road traffic. It defines key traffic-related terms and outlines the standard process for conducting a traffic impact assessment. This involves collecting existing traffic data, conducting traffic surveys, analyzing current and projected traffic levels, estimating new traffic from the project, and determining if mitigation measures are needed to maintain adequate traffic flow. The assessment process helps identify impacts and inform planning to reduce congestion.
Traffic census and analysis (a case study)eSAT Journals
Abstract Traffic Census is the baseline of Transportation Engineering. All management as well as engineering operations are done on the
basis of this only. There is a considerable variations in flow, so for the purpose of designing averaging of these counts is done into
single volume count. There are four main methods of Traffic Census namely Manual Method, Automatic Method, Combination of
Manual and Automatic Method and Photographic Methods. All these have their pros and cons. These have different preferences
with respect to Accuracy, ease of Documentation, Versatility and economics. Three main methods of Traffic Analysis IRC, U.K
method and U.S.A practices have been discussed along with IOWA Department of Transport guidelines for measurement of
Congestion. For better management of Traffic, duration of Survey as per IRC has to be increased as urban areas are moving from
Developed to developing. Sanat Nagar/Rawalpora Intersection is the most important that is encountered in 17.8km stretch of
NH1A Bypass which is expected to be the jugular Vein of the Greater Srinagar City. It can be considered as a place where whole
of Kashmir meets. A case study of Traffic Census and Analysis of the said intersection is presented.
Keywords: Traffic Census, Traffic Analysis, Transport
This document discusses challenges in designing complex interchanges in densely populated urban areas. It begins by describing a hypothetical motorist's anxiety navigating an unfamiliar complex interchange. Complex interchanges contain many lanes and ramps, requiring intense driver attention. The document provides guidance for highway designers on issues like ramp spacing, guide signing, route continuity, and lane balance. It highlights the reconstruction of the I-85/SR-316 interchange in Atlanta as an example of improving safety and mobility through the use of collector-distributor roads and other design elements. Clear guide signing is important to help drivers understand how to navigate through complex interchanges.
TE004, A Study On Feasible Traffic Operation Alternatives At Signalized Inter...Saurav Barua
This study analyzed traffic operations at a busy signalized intersection in Dhaka, Bangladesh using traffic simulation software VISSIM. Four alternatives were considered: 1) banning right turns, 2) optimizing signal timing, 3) constructing a one-way overpass, and 4) constructing two overpasses. Traffic data was collected and used to calibrate the VISSIM model. The alternatives were then simulated and evaluated based on average speed, delay, and queue length. Constructing a single overpass was found to provide the greatest benefits, increasing average speed by 250% and reducing delays and queues by over 90%, making it the recommended alternative to improve traffic flow at the intersection.
Study the Effects of Traffic Situation on Driver’s Mood and Root Choice Decis...ijtsrd
This document summarizes a research study that analyzed how traffic situations affect drivers' moods and route choice decisions in commercial areas. Specifically, it used a traffic analysis software to count vehicles on a broad lane and service lane over time. It found that traffic peaks during rush hours affected both lanes similarly. Increased traffic and longer traffic light wait times encouraged drivers to use the alternate service lane, increasing congestion there and accident risk. The key finding was that longer traffic light wait times were the most important factor influencing drivers' decisions to use the service lane. Reducing wait times could impact typical use of the broad and service lane and improve overall traffic management.
Study of Road Safety Audit in Municipal Area’sIRJET Journal
This document summarizes a study of road safety at an intersection near Akurdi railway station in Pune, India. Traffic and pedestrian surveys were conducted at the intersection, called Dharmraj Chowk. The studies found traffic volumes exceeding the road's design capacity and insufficient width of footpaths for pedestrians. Issues identified included improper lane markings, missing pedestrian signals and signs, and an improperly arranged traffic island. The study aims to conduct a road safety audit, identify safety deficiencies, and develop mitigating strategies to improve safety for vehicles and pedestrians at the intersection.
Simulation of pedestrian at intersection in urban congested areaeSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
1 illinois ps a study-on_the_safety_of_left_side_off_ramps_on_freewaysSierra Francisco Justo
This study evaluated the safety of four left-side off-ramps on freeways in Tampa Bay, Florida. The researchers conducted an in-field observation of traffic flows, identified four types of traffic conflicts, and analyzed crash records of left-side off-ramps and similar right-side off-ramps. They found an average conflict rate of about 10 per 1,000 vehicles near left-side off-ramps and that 5% of vehicles made lane changes, including 15% aggressive last-minute changes. Crash rates for left-side off-ramps were higher but within expected critical crash rates. The study recommends no special improvements for left-side off-ramps.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Performance evaluation of santasi roundabout, kumasi ghana using micro simula...eSAT Journals
Abstract Roundabouts are an increasingly popular alternative to traffic signals for intersection control in the United States. Roundabouts have a number of advantages over traffic signals depending on the conditions. They reduce the severity of crashes since head-on and right-angle conflicts are nearly eliminated. They reduce through traffic speeds to provide a “calmer” roadway environment. They may consume less land area since turn pocket lanes are not needed and also have lower energy and maintenance costs. This study evaluated performance of Santasi roundabout in Kumasi, Ghana using micro simulation model. Traffic and geometric data were collected on the field. The analysis revealed that Santasi roundabout was operating at a level of service F, which represented worst conditions. Signalized intersection with 4 approach lanes was proposed to control all the movements. Exclusive pedestrian phases were proposed to protect pedestrians. Index Terms: Performance evaluation, Santasi roundabout, Capacity analysis, Transportation network performance
The spectacular growth of the automobile as one of the most convenient modes of travel has brought in its wake frustrating problems of parking, accidents, delay, congestion, etc. It is no longer sufficient to build roads of adequate structural strength to cater to the needs of vehicles, but it is equally important that the safe, efficient and comfortable movement of traffic and other road user is ensured on these roads. Highway intersections are nodes of road networks and accident - prone locations. They are the places where vehicles coming from different approaches and moving towards different directions interact and conflict with each other. Due to the conflicts from all users, more traffic crashes could happen at unsignalized intersection as compared with roadway segments. This study is fully based on the existing conditions of unsignalized intersection, including geometric design, sight distance, traffic control devices etc. The problems of parking, accidents and delay are also prevailing in the area under our study i.e. intersection at 26th mile. The intersection is an unsignalized one and therefore, the chances of accidents during the peak hours are very high. Since, it is a meeting point of a national highway and a state highway, the variation in the design speed of both roads also interrupts the traffic flow. Our study on the intersection at 26th mile mainly aims at improving the geometrical as well as the safety features of the intersection like accident control by signal installation, incorporation of proper sight distances, uninterrupted traffic flow without causing crashes, delay, etc.
Evaluation of level of service at chatikara, MathuraSHASHANK KAMAL
Evaluation of level of service. Level of service (LOS) is a qualitative measure used to relate the quality of traffic service. LOS is used to analyze highways by categorizing traffic flow and assigning quality levels of traffic based on performance measure like speed, density,etc.
Designing of a Traffic Signaling System at T-IntersectionIJERA Editor
The traffic signal design of the intersection has a direct control on its safety and operation from a design and user-ability point of view. We identified Kothavalasa T-Intersection has been arise problems like road accidents, conflicts and congestions. Design elements that are particularly important include the number of lanes provided on each approach and for each movement. These problems can solve by providing an efficient traffic signal control at the intersection for continuous movement of vehicles through the intersection. According to traffic signal, most traffic signal timing plans are designed to minimize vehicle delay based on the volumes seen in the past, not the present. Traffic count studies are to be made to determine the number, movement and classification of vehicles at an intersection. Signal timing is most important which is used to decide green time of the traffic light shall be provided at an intersection and how long the pedestrian walk signal should be provided. By using Highway Capacity Manual (HCM) intersection saturation for identifying periods of time when cycle length could be substantially short. These data is used identify normal flow of the roadway; determine the influence of heavy vehicles or pedestrians on vehicular traffic volume. Webster’s minimum delay cycle length equation overestimates the optimal cycle length compared to the results based on the HCM 2000 method. This is due to the restructuring of the HCM 2000 delay equation as compared to the original Webster’s delay calculation.
The document summarizes the first educational meeting of the North Carolina SimCap volunteer network. It includes an overview of the North Carolina SimCap organization, its objectives of developing professionals, strengthening relationships, and advancing the traffic simulation profession. It also summarizes two presentations on the history and activities of North Carolina SimCap and the application of transportation modeling and simulation in the planning process. Finally, it discusses the results of a survey on the network's objectives, preferred meeting topics and activities, and members' experience and interest in different traffic simulation tools.
In this paper, I argue that modern roundabouts are a highly favorable solution for roadway intersections because of their benefits with regards to safety, environmental factors, and traffic flow efficiency. I begin by addressing public opinion of roundabouts and then explaining their safety benefits. Next, I demonstrate how roundabouts can overcome commonly perceived drawbacks related to usage by pedestrians, cyclists, oversize vehicles, and emergency vehicles. The penultimate sections are devoted to the cost and land considerations and the environmental benefits associated with roundabouts. Lastly, I show how roundabouts improve traffic flow efficiency and conclude that, all factors considered, roundabouts are a highly favorable design solution.
The document discusses different types of road intersections and design considerations. It describes two main types - grade-separated intersections which use overpasses or underpasses to eliminate conflicts, and at-grade intersections where roads intersect on the same level. Some key intersection types are discussed including diamonds, cloverleafs, and roundabouts. Design elements like capacity, traffic control, sight distances, and vehicle turning radii are also covered.
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ABSTRACT
Three interchange alternatives were studied to determine their impact on morning
and evening peak hour traffic flow. An interchange is the roadway system where freeways are
connected to either freeway or arterial/local road.
Freeway – Freeway is known as System Interchange
Freeway – Arterial/Local Road is known as Service Interchange
This study is mainly concerned about Service Interchanges. Interchanges are of the diamond
configuration, and interchanges using roundabouts or loop ramps are also popular. Over the
years in United States these interchanges were built and maintained. Interchange helps
reducing conflict points where the pedestrian safety plays key role. Selected interchange has
different conflict points as a matter of fact
Contraflow Left Interchange – 20 Conflict Points
Displaced Left Interchange – 18 Conflict Points
Modified Single Point Interchange – 14 Conflict Points
There are number of measures used to make an interchange safer than it used to be. This
report includes the couple measures for improving safety.
An efficient freeway system will be essential for the growth of any country and
interchanges are important to that efficiency. However, many diamond interchanges have
serious operational problems, interchanges with roundabouts fail at high demand levels, and
loops use lots of expensive land. The study was conducted to find the level of service for the
existing condition. For the above interchanges level of service was found for the present year
(2014 - 2015)
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ACKNOWLEDGEMENT
I heartily want to thank Dr. Joseph E Hummer for giving me this wonderful
opportunity to discover something new about these alternative designs.
I want to thank each and every official from the government agencies and the
private agencies who have supported in a timely manner for this study by
providing the required details to complete my study on those designs
Florida Department of Transportation (Sawgrass Turnpike Enterprise)
Texas Department of Transportation (Victor Vargas)
Crawford, Murphy & Tilly, Inc. (Brian Eads, MO)
Without your help this is nothing but a piece of junk. The data you provided
made this quite decent portion of the report.
Sincerely,
Srikant S Rao
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Table of Contents
Sl. No. Description Pg. No.
Abstract 2
0.1 Introduction 6
0.2 Terminology 6
0.3 Objective 6
0.4 Interchanges for the study 6
0.5 Difference between the designs 7
0.6 Pros & Cons of all 3 designs 7
CHAPTER 1 - Contraflow Left Interchange
1.1 Introduction 8
1.2 Inventory of the design 9
1.3 Typical Roadway Geometry 10
1.4 Design and Operations 10
1.5 Signing and Signboards Diagram 11
1.6 Traffic Signal Control 11
1.7 Applicability 12
1.8 Turning Movement Counts 12
CHAPTER 2 - Displaced Left Interchange
2.1 Introduction 13
2.2 Inventory of the design 13
2.3 Design and Operations 14
2.4 Typical Roadway Geometry 15
2.5 Traffic Signal Control 16
2.6 Applicability 16
2.7 Signing and Signboards Diagram 17
2.8 Turning Movement Counts 18
CHAPTER 3 - Modified Single Point Interchange
3.1 Introduction 19
3.2 Inventory of the design 20
3.3 Typical Roadway Geometry 20
3.4 Design and Operations 21
3.5 Signing and Signboards Diagram 21
3.6 Traffic Signal Control 21
3.7 Applicability 21
3.8 Turning Movement Counts 22
CHAPTER 4 - Synchro Analysis
4.1 Analysis Tool 23
4.2 Contraflow Left Interchange Analysis 24
4.3 Displaced Left Interchange Analysis 27
4.4 Modified Single Point Interchange Analysis 30
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Table of Exhibits
# of
Exhibit
Design Description
Pg.
No.
Exhibit 1
CFI
Example 8
Exhibit 2 Inventory 9
Exhibit 3 Typical Roadway Geometry of CFI 10
Exhibit 4 Signing and Signboard Diagram 11
Exhibit 5 NB/EB Daily Traffic 12
Exhibit 6 SB/WB Daily Traffic 12
Exhibit 7
DLT
Inventory in SL-82 at I-35 13
Exhibit 8 Inventory in SL-82 at I-35, Google Maps 14
Exhibit 9 Inventory in SR-80 at I-35, Google Maps 14
Exhibit 10 Typical Design of DLT 15
Exhibit 11 Typical Roadway Geometry of DLT 16
Exhibit 12 Pedestrian Accommodation in DLT 16
Exhibit 13 Signing and Signboard Diagram 17
Exhibit 14 Peak Hour Volume of I-35 at SR-80 18
Exhibit 15 Peak Hour Volume of I-35 at SL-82 18
Exhibit 16
MSP
Inventory 20
Exhibit 17 Typical Roadway Geometry of MSP 20
Exhibit 18 Signing and Signboard Diagram 21
Exhibit 19 Annual Average Daily Traffic 22
Exhibit 20 LOS Chart 23
Exhibit 21
CFI
Synchro Model for CFI 24
Exhibit 22 Synchro Model for CFI with Nodes 25
Exhibit 23 Synchro Model for CFI with LOS 26
Exhibit 24
DLT
Synchro Model for DLT 27
Exhibit 25 Synchro Model for DLT with Nodes 28
Exhibit 26 Synchro Model for DLT with LOS 29
Exhibit 27
MSP
Synchro Model for MSP 30
Exhibit 28 Synchro Model for MSP with Nodes 31
Exhibit 29 Synchro Model for MSP with LOS 32
CFI - Contraflow Left Interchange
DLT - Displaced Left Interchange
MSP - Modified Single Point Interchange
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0.1. Introduction
In any road transportation system, an interchange is a road connection that normally
uses grade separation, by providing one or more ramps to permit the traffic on at least one
highway to get through the junction without crossing any other traffic stream. It differs from a
standard intersection, at which roads cross at grade. Interchanges are almost always used
when at least one of the roads is a controlled-access highway known as freeway or a limited-
access divided highway known as expressway, though they may occasionally be used at
junctions between two surface streets (Wikipedia)
0.2. Terminology
1. A freeway or highway interchange is a type of road linkup, linking one highway to
another; to other roads; or sometimes to just a motorway service station. In the U.S.,
interchanges are either numbered according to cardinal interchange number, or by
mileage (typically the latter in most states).
2. A highway ramp (as in exit ramp / off-ramp and entrance ramp / on-ramp) (North
American usage) or slip road is a short section of road, which allows vehicles to enter
or exit a controlled-access highway (freeway).
3. A directional ramp always tends toward the desired direction of travel. This means
that a ramp that makes a left turn exits from the left side of the roadway (a left exit).
Left directional ramps are relatively uncommon as the left lane is usually reserved for
high-speed through traffic. Ramps for a right turn are almost always right directional
ramps. Where traffic drives on the left, these cases are reversed.
0.3. Objective
The interchanges are very massive in usage all over United States implemented after
careful study of the location and reviewing the requirements of roadway users (Traffic Volume
and Crashes). This study is to know about the pros and cons of these Interchanges and what
will be the measure undertaken to mitigate the problem of delay/crashes and finding out
better design for implementing.
0.4. Interchanges considered for this study
In United States there are lot of Interchanges, let me put that up in a common
language that is connecting freeway to freeway/arterial/local road wherein intersection
basically connecting local road to arterial. As US Department of Transportation encouraging
every state to implement new designs, State Department of Transportation professionals are
coming up with designs, which help in reducing delay and increasing safety.
Below is the list of the interchanges considered for this study. Study is mainly based
on these types of interchanges.
Contraflow left interchange (Modified TUDI)
Displaced left turn interchange (Continuous flow interchange)
Three-point interchange (Modified single point interchange)
The study is reporting the safety aspects of all three designs for implementing. It is important
because of the crashes occurring in new designs lately. Although there will be direction
installed why crashes are happening. Nearly 35% of the crashes happening because of this
factor mentioned above. 6 out of 10 pedestrians are the victims for this kind of crashes. To
reduce this kind of crashes we need to
Educate drivers
Install legible signs
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0.5. Differentiating mentioned designs:
Factors
Influencing
Contraflow Left
Interchange
Displaced Left Turn
Interchange
Modified Single
Point
Interchange
Where’s
design located
One in State of
Florida, State
Route 869 at
Lyons Rd,
Coconut Creek,
Sunrise, FL
2 in State of Texas, city of San
Marcos One in State of
Missouri, I-55 at
State Route 141,
Arnold, MO
I-35 at Aquarina Springs Drive
&
I-35 at State Route 80
Where’s
design
applicable
Both for freeways
and arterials
Both for freeways and arterials Freeways only
# Of
Pedestrian
Conflict Points
20 Conflict Points 18 Conflict Points 14 Conflict Points
Width of
bridge size
6 Lanes 6 Lanes 4 Lanes, 2 Ramps
Traffic control
used
2 at 3 Phase
Signal
4 at 2 Phase Signal 3 at 2 Phase Signal
Phase addition
for frontage
road
No No Yes
Analysis tool
used
Synchro Studio 8 Synchro Studio 8 Synchro Studio 8
Where the
design can be
implemented
Low to moderate left-turn volumes from the off-ramp to the arterial.
Heavy and balanced through volumes on the
arterial roadway.
Moderate to heavy left-turn volumes from the
arterial to the on-ramp.
0.6. Pros and Cons of these designs:
Design
CONTRAFLOW LEFT
INTERCHANGE
DISPLACED LEFT
INTERCHANGE
MODIFIED SINGLE POINT
INTERCHANGE
Pros
Low critical sum Low critical sums Low critical sums
-
Offers benefit over conventional
diamond
Compact along arterial
- - Signal phasing
Cons
Wide bridge
Pedestrians must cross free flow
ramps
Large bridge
- Wide bridge -
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CHAPTER 1
CONTRAFLOW LEFT INTERCHANGE
1.1. Introduction:
A contraflow left interchange is also known as Modified Tight Urban Diamond Interchange.
Cross Street left turns crossover opposing left turn movements in storage bays prior to the
first ramp intersection. Vehicles move into contraflow lanes within the interchange, before
making the turn onto the ramp. These special lanes run in the opposite direction from the
adjacent thru-lanes, and provide additional storage for left turn vehicles. (Exhibit 1)
Exhibit 1 – Example of contraflow left interchange design
Source: Wikipedia
Diagram showing a glimpse of how does this (Contraflow Left Interchange) design
look like and it’s not typical overview of the interchange.
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1.2. Inventory of the Design:
First state in United States to introduce this new design and was implemented in 1960s
at the intersection of RT 7 with US 441 in Sunrise, Florida. The design replaced a Tight
Diamond interchange that was failing due to the number of signal phases. A narrow overpass
and business development tight to the arterial right-of-way prohibited the possibility of
adding adequate opposing left-turn bays at the interchange approaches. Therefore the
contraflow lanes, which are built within the intersection, were introduced. Originally the
design was to be an interim solution until funds were made available to reconstruct the
interchange. However, the design worked well for nearly 20 years until the bridge was
rebuilt in the 1980s. Today, there are at least two other known CFL interchanges still in
operation in Florida, one of which was originally constructed as a CFL. Lyon Creek Parkway
underneath Florida State Route 869 switching the left turn lanes on the cross streets each other
and bringing the long left turn phases from the single point urban interchange to the TUDI at
26.301177°N 80.186479°W. (The co-ordinates directs to the picture below in Google maps)
Exhibit 2 – Contraflow Left Interchange existence
Source: Google Maps: Located on Lyons Rd and State Route 869, Florida.
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1.3. Typical Roadway Geometry:
Exhibit 3 – Typical Roadway Geometry of Contraflow Left Interchange
Source: Unconventional Arterial Intersection Design by Gitbooks
The arterial/local road having 2 through lane, 1 left lane (depends on volume) and 1
right lane before the bridge.
Those 2 thru lanes continue on the bridge, which should be typical.
Two medians on the arterial one is 12-20ft wide (before the bridge), which separates
left from through and right lanes. Another is three 4ft wide to separate the oncoming
through from left lane and also from the same direction thru movement as in Exhibit 3
Ramps having minimum of 2 lanes one for right, one for thru & left shared turning
movements.
Providing signal on either side of the bridge, which is 3-phase. Install all the
mentioned requirements like signage and sign boards for the design as shown in
Exhibit 4
1.4. Design and Operations:
The CFL design is a disparity on the Diamond interchange, and is best used as an
alternative to a Standard Diamond interchange.
All movements in a CFL interchange are the same as those of a typical Diamond
interchange configuration except for left turns from the cross street. Cross street left
turns move over into left turn storage lanes (separated from the cross street through
lanes by raised median) approximately 300 feet prior to the first ramp intersection.
Vehicles precede the first signal and into contraflow lanes within the interchange,
before making the turn onto the ramp. These lanes run in the opposite direction from
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the adjacent through-lanes, and overlap within the interchange. (Ref. UAID)
The CFL design reduces the number of signal phases compared to a Tight Diamond
interchange from four to three by allowing the two opposing left-turn movements to
be made during the same signal phase.
The same requirements for additional intersection clearance time exist in the CFL
design as with both SPUI and Standard Diamond interchange designs.
The greatest design benefit of the CFL is in the extra capacity from the left turn
vehicles being able to move during two phase instead of one.
1.5. Signing and Signboards Diagram:
Exhibit 4 – Signing and Signboard Diagram
Picture Source: Unconventional Arterial Intersection Design (Referred Google Earth street view for Signs)
This portion of the design is very important to keep the safety aspect on top. New
designs keep on coming where the major factor, which affects safety, is driver’s confusion. It
plays a vital role while thinking about safety. This is to educate drivers by installing signing
and sign boards.
Above picture shows the red dot explaining left exit. It doesn’t mean it’s an exit from a
freeway. Tried finding the signboard, but couldn’t find the right signboard used in Florida
that tells left exit only.
1.6. Traffic Signal Control:
A contraflow left interchange basically has traffic signals at each of the two ramp
intersections. Signal control at each of these four junctions operate with just two phases which
are co ordinated with the subsequent signal connecting entry ramps and opposing thru traffic
having 3 phases for the alternative conflicting movements and are coordinated to maintain
progression on the arterial road.
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1.7. Applicability:
The contraflow left interchange design should be taken into consideration for the location
where it has some reflecting factors below,
Heavy and balanced through volumes on the arterial roadway.
Moderate to heavy left-turn volumes from the arterial to the on-ramp.
Low to moderate left-turn volumes from the off-ramp to the arterial.
Limited bridge deck width, but right-of-way is available on the bridge approaches.
1.8. Turning Movement Counts:
Exhibit 5 – NB/EB daily turning count
Enterprise Turnpike System
Segment Sawgrass Expressway
Facility SR869 Lyons Rd NB off
FLDOT
Northbound/Eastbound
Non Sun Pass Sun Pass Directional
Total50S Toll Type Total 50S Toll Type Total
Total 14039 14039 111473 111473 125512
Average Daily 453 453 3596 3596 4049
Exhibit 6 – SB/WB daily turning count
Enterprise Turnpike System
Segment Sawgrass Expressway
Facility SR869 Lyons Rd SB on
FLDOT
Southbound/Westbound
Non Sun Pass Sun Pass Directional
Total60S Toll Type Total 60S Toll Type Total
Total 15523 15523 124206 124206 139729
Average Daily 501 501 4007 4007 4507
Source: Florida Department of Transportation
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CHAPTER 2
Displaced Left Interchanges
2.1. Introduction:
The DLT interchange, also known as the continuous flow interchange, is an innovative
interchange design that has several aspects similar to the at-grade DLT intersection and some
aspects similar to the DCD interchange. At the time of this report, no known implementations
of this treatment could be identified. Moreover, there was no patent on the DLT interchange
design. Nevertheless, it is a design treatment that has been advocated as promising because
it removes the conflict at the main intersection between left turning and opposing through
vehicles.
The main feature of the DLT interchange design is the left-turn crossovers that are
present on the cross street approaches. In a DLT intersection, the left-turning traffic is
relocated at a location several hundred feet upstream of the first signal-controlled ramp
terminal of the diamond interchange. This left-turning traffic is crossed over the opposing
through lanes. This traffic then travels on a new roadway that is situated between the
opposing through lanes and a roadway and that carries the right-turning traffic from the ramp.
These drivers then make the left turn onto the ramp. (FHWA - AIIR)
2.2. Inventory of the Design:
TxDOT, in partnership with the city of San Marcos, has made intersection improvements to
1. SH 80 (Hopkins Street) at I-35, San Marcos, TX
2. Loop 82 (Aquarena Springs Drive) at I-35 in San Marcos to improve operations at
these intersections.
One is a single-leg CFI at the intersection of State Highway Loop 82 (Aquarena Springs Drive),
Interstate 35's southbound frontage road and I-35's southbound-to-northbound Texas U-turn
(29.893048°N 97.913367°W)Construction completed in the month of May, 2014.
Exhibit 7 – Displaced Left Interchange (1 legged)
Located in Aquarina Spring Dr at I-35, San Marcos, TX
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Exhibit 8 – 1-Legged CFI
Source: Google Maps, Aquarina Springs Dr at I-35, San Marcos, TX
The satellite view of Exhibit 6 is not updated in Google maps because this construction has
finished recently in May 2014. Google maps satellite view was last updated in 2013.
The other, a two-leg CFI, is at the intersection of State Highway 80 (Hopkins Street), I-35's
frontage roads and I-35's Texas U-turns (29.882639°N 97.921915°W). The estimated cost for
both CFIs is $4.7 million.
Exhibit 9 – 2-Legged Continuous Flow Interchange
Source: Google Maps located on SR-80 at I-35, San Marcos, TX
2.3. Design and Operations:
The DLT interchange is a new interchange design that has similarities to both at-grade
DLT intersection and the double crossover diamond (DCD) interchange.
The main feature of the DLT interchange is that left-turning traffic crosses over the
opposing through lanes several hundred feet upstream of the main intersection and
then proceeds on a new roadway situated between the opposing through lanes and a
roadway that carries right-turning traffic from the ramp.
From this new roadway, the left-turn traffic completes its maneuver onto the on-ramp.
A DLT interchange has four signalized junctions: two at the crossovers for the DLT
movements and two at the ramp terminals of the interchange.
The DLT interchange design reduces the number of phases at the signal-controlled
ramp terminals within the interchange from three to two, thereby reducing delays to
drivers, pedestrians, and bicyclists as they pass through the interchange area.
To ensure the smooth progression of traffic, all four signalized junctions are operated
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in a coordinated system.
A DLT interchange has the same number of conflict points as a conventional diamond
interchange. However, fewer angle crashes may be anticipated in a DLT interchange
compared with a conventional interchange because conflicts are more separated.
(AIIR – FHWA)
2.4. Typical Roadway Geometry:
Exhibit – 10 - Typical Design of Displaced Left Interchange
Source: FHWA
The primary design elements of a DLT interchange (Exhibit 11) are as follows:
• Left-turning traffic is displaced from the main intersection by adding lanes that allow traffic
to cross the opposing through traffic at a signal-controlled location 400 to 500 ft upstream of
the main intersection.
• Radii of the crossover movements range from 150 to 200 ft, and radii of the left-turning
movement at the interchange nodes depend on the turning path of the selected design
vehicle (Exhibit 11).
• A larger overall interchange footprint may be needed, given that major road left-turning
vehicles travel on the opposite side of the roadway, requiring a wider median.
• U-turn movements on the arterial roads are prohibited in the interchange area, similar to
the DLT intersection.
• Access to adjacent properties is limited by the interchange design, and accommodation of
individual driveways is considered on a case-by-case basis.
• Pedestrians can be accommodated in a DLT interchange as shown in Exhibit 12. (AIIR –
FHWA)
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Exhibit 11 - Typical Roadway Geometry
Source : FHWA
Exhibit 12 – Pedestrian Accommodation
Source : FHWA
2.5. Traffic Signal Control:
A DLT interchange typically has traffic signals at each of the two left-turn crossovers and at
each of the two ramp intersections. Signal control at each of these four junctions operate with
just two phases for the alternative conflicting movements and are coordinated to maintain
progression on the arterial road. Traffic signals at a DLT interchange are fully actuated to
minimize delay. (AIIR – FHWA)
2.6. Applicability:
The DLT Interchange design should be taken into consideration where it is reflecting
the same factors below, (AIIR – FHWA)
Limited bridge deck width, but right-of-way is available on the bridge approaches.
Moderate to heavy left-turn volumes from the arterial to the on-ramp.
Low to moderate left-turn volumes from the off-ramp to the arterial.
Heavy and balanced through volumes on the arterial roadway.
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2.7. Signing and Signboard Diagram:
Exhibit 13 – Displaced Left Turn at SR-80 & I-35, San Marcos, TX
Source: Victor Vargas (TxDOT)
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2.8. Turning Movement Counts:
Exhibit 14 – Peak hour volume of I-35 at SR-80
Exhibit 15 – Peak hour volume of I-35 at Aquarina Springs Drive (SL-82)
Source: Victor Vargas (TxDOT)
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CHAPTER 3
MODIFIED SINGLE POINT INTERCHANGE
3.1. Introduction:
Modifying a single-point interchange is not a standard design and is not
discussed in most published literature on interchange design. This could be because most of
this literature does not deal with large skew angles. As quoted earlier, the AASHTO design
guide only states that “extreme care” should be used when designing single-point
interchanges with a skew greater than 30 degrees. This site has a skew nearly double that
threshold. The AASHTO design guide does not provide any additional guidance in the design
of interchanges with such a severe skew.
The modified single-point interchange design takes advantage of the skew to provide
smooth left turn movements at the interchange. The off-ramp lefts are brought together at the
middle of the bridge and controlled by one signal similar to the single-point. Because of the
skew, these approaches meet the arterial at about a 15-degree offset. These approaches do
not require the large clearance distance and time that are associated with the traditional
single-point interchange movements. The on-ramp left turn movement geometrics are similar
to the diamond interchange. Each of the on-ramp left turn movements is controlled by
separate signals. A nonstandard bridge design is required. This bridge is similar to the
single-point interchange, but smaller because only two ramps meet at the bridge, which do
not require a larger bridge deck for support. This design is similar to the diamond
interchange in that the on-ramp left turns occurs at either end of the interchange. Through
traffic on the arterial can be stopped by up to two signals, with the third signal giving
continuous green for the through movement. The design is comparable to the single-point
interchange because the off-ramp lefts are brought together at the middle of the interchange.
The main operational characteristic, which is unique the modified single-point design, is that
each of the three signals has two phases and the signals are spaced far enough apart to allow
adequate storage between the signals.
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3.2. Inventory of the design:
Missouri is the first state to introduce and implement this design for the first time. This
design is constructed one in the state of Missouri that is on MO-141 at I-55, Arnold, MO.
Crawford, Murphy & Tilly, Inc. a consulting company took over this project to find the right
alternative for the area where there was a serious problem of crashes and intersection delay.
The below design was the best of the alternatives they found.
Exhibit 16 – Location of the design
Source: Google Maps, located on MO-141 at I-55, MO
3.3. Typical Roadway Geometry:
Exhibit 17 – Modified Single Point Interchange
Source: AutoCAD self-designed (Not to Scale)
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12ft of lane width used on both arterials and freeway
10-11ft on all side of ramps
2 phase signal on all 3 signal location
Centre median could be minimum of 4ft wide
Median near the ramps could be 12-20ft wide
Install the signboards as below
3.4. Design and Operations:
Design is found in exhibit 17 part of the design. This design have 2 kind of ramps, one
is Directional ramps (NB/SB or WB/EB) another is center ramps with left turn lanes which has
moderate to heavy left turns from freeway to arterial. All directional through movements are
coordinated with the consecutive signals ahead of them.
3.5. Signing and Signboard Diagram:
Exhibit 18 – Signing and pavement marking diagram
Source: Self-designed using Google Earth Street View
3.6. Traffic Signal Control:
A modified single point interchange typically has traffic signals on 3 sides where 2 on either
side of the bridge where the ramps connect to the arterial/local road and 1 at the center
where 2 directional thru movement and 2 directional left ramps connecting arterial. Signal
control at three junctions operates with just two phases for the alternative conflicting
movements and are coordinated to maintain progression on the arterial road.
3.7. Applicability:
The modified single point interchange design should be taken into consideration where it is
reflecting the same factors below,
Moderate to heavy left-turn volumes from the arterial to the on-ramp.
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Moderate to heavy left-turn volumes from the off-ramp to the arterial.
Heavy and balanced through volumes on the arterial roadway.
3.8. Turning Movement Counts
Exhibit 19 – Annual Average Daily Traffic Volume
Source: Crawford, Murphy & Tilly, Inc., MO
Turning Movement Count Summary - MO 141 and I-55 Southbound Ramps
Typical Weekday
Hour Southbound Westbound Northbound Eastbound Total
Beginning Left Through Right Left Through Right Left Through Right Left Through Right Volume
TOTAL 0 13,723 7,357 0 0 0 4,689 13,561 0 0 0 0 39,330
Turning Movement Count Summary - MO 141 and I-55 Southbound Ramps
Typical Saturday
Hour Southbound Westbound Northbound Eastbound Total
Beginning Left Through Right Left Through Right Left Through Right Left Through Right Volume
TOTAL 0 13,530 7,110 0 0 0 5,912 12,978 0 0 0 0 39,530
Turning Movement Count Summary - MO 141 and I-55 Center Ramp
Typical Weekday
Hour Southbound Westbound Northbound Eastbound Total
Beginning Left Through Right Left Through Right Left Through Right Left Through Right Volume
TOTAL 0 13,242 0 7,273 0 8,282 0 10,637 0 7,151 0 6,112 52,697
Turning Movement Count Summary - MO 141 and I-55 Center Ramp
Typical Saturday
Hour Southbound Westbound Northbound Eastbound Total
Beginning Left Through Right Left Through Right Left Through Right Left Through Right Volume
TOTAL 0 13,098 0 6,435 0 6,874 0 12,250 0 6,128 0 7,677 52,462
Turning Movement Count Summary - MO 141 and I-55 Northbound Ramps
Typical Weekday
Hour Southbound Westbound Northbound Eastbound Total
Beginning Left Through Right Left Through Right Left Through Right Left Through Right Volume
TOTAL 7,131 13,882 0 0 0 0 0 10,878 6,164 0 0 0 38,055
Turning Movement Count Summary - MO 141 and I-55 Northbound Ramps
Typical Saturday
Hour Southbound Westbound Northbound Eastbound Total
Beginning Left Through Right Left Through Right Left Through Right Left Through Right Volume
TOTAL 6,085 13,889 0 0 0 0 0 12,455 5,945 0 0 0 38,374
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CHAPTER 4
SYNCHRO ANALYSIS
4.1. Analysis Tool:
Considered using Synchro 8. Synchro Studio is robust, easy-to-use traffic signal
software that helps traffic engineers and transportation planners design, model, optimize,
simulate, and animate signalized and un-signalized intersections (including roundabouts),
delivered in a comprehensive, standardized file format.
Synchro 8 is a suitable tool to find out the intersection delay, level of service of an
intersection, intersection splits and offsets because for VISSIM we need to have the exact
signal timing to run the model, wherein synchro we don’t need to worry about the signal
timings as it gives by itself. Below are the exhibits to show how the interchanges were
designed in sychro model
Main aim of using this software is to find out the level of service at the intersections. If
it is worse, trying to find better way to improve the intersections which is cost beneficial.
Below attached is the chart for finding the level of service with the help of intersection delay
in seconds per vehicle.
Exhibit 20 – LOS Chart
Source: Wikipedia
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4.2. Contraflow Left Interchange Analysis:
Exhibit 21 – Synchro Model for Contraflow left Interchange
Source: Trafficware Synchro 8 – Self Designed (Not to Scale)
This interchange took lot of time to complete because of lot of errors occurred while
going through the design. I worked on all of the factors, where the errors were popping up
when I checked code of the design application. Initially encountered more than 20 errors and
10 warnings. Now there is no single error in the model and some warnings are still present
but it’s not a serious issue, which affect the results. Design consists of 4 - 2Φ signal and 2 - 3Φ
signal on either side of the bridge. The analysis was carried out for the volume data (Courtesy
of Florida Department of Transportation). Detailed report of synchro analysis is attached in
the appendix part of the report.
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Below attached exhibit explains the number of nodes and intersections used in the design for
modeling purposes.
Exhibit 22 – Contraflow Left Interchange with # of nodes
Source: Trafficware Synchro 8 – Self Designed (Not to Scale)
As you can see the exhibit above having number of nodes present in the design
where the number with white boxes say those are signalized intersection and the numbers
with blue boxes say those are nodes where 2 roads connect making an angle except node 25
and 29 are un-signalized intersection with yield sign.
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Below exhibit shows the contraflow left design with the level of service on all intersections.
Exhibit 23 – Contraflow Left Interchange with LOS
Source: Synchro 8 (Self-designed - Not to Scale) (Volume data - Courtesy of FLDOT (Sawgrass Turnpike Enterprise))
As the volume data provided by Florida department of transportation mentioned
above. Those data were implemented for the existing condition. The Level-of-service turned
out to be like as in the exhibit above. The nodes with level of service U refer to a node or un-
signalized intersection. (Yield Sign, Stop Sign, Free)
Methodology:
After designing this model above shown in exhibit 23 in synchro. The volumes are
entered provided by Florida department of transportation (Sawgrass Turnpike
Enterprise).
The volume were provided for vehicles passing the in and out of the tollgates. Both on
ramps have tollgates installed. Volume data were divided into toll passed vehicles
and toll not passed vehicles.
By the evaluating engineering consideration I assumed the numbers for the turning
counts.
Initially I found the level of service to be F on 4 intersections in the middle. Later I
played with the intersection cycle length to make it D.
Tweaked the Signal timings a bit which helped me to achieve level of service B on all
those 4 intersections in the middle. This is the least possible way to make an
improvement
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4.3. Displaced Left Interchange Analysis:
The design was pretty tough compared to the contraflow and modified single point
because of the displaced left as we can see in exhibit 22. There was lot of errors and warnings
in this design as well, still there are warnings, which does not affect the result part of the
design but no errors in code check.
Exhibit 24 – Synchro Model for Displaced Left Interchange
Source: Trafficware Synchro 8 – Self Designed (Not to Scale)
This interchange took lot of time to complete because of weaving part in the design as
shown in the above figure. There are 2 - 2Φ and 2 - 1Φ signal on either side of the bridge. On
the bridge it should be 4 – 2Φ here there are 6 that’s because of the limitations of synchro. The
minimum distance between the intersections should be maintained 100ft. The analysis was
carried out for the volume data provided (Courtesy of Victor Vargas, Texas Department of
Transportation). Detailed report of synchro analysis is attached in the appendix part of the
report.
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Below is the exhibit showing the design with number of nodes on it.
Exhibit 25 – Displaced Left Interchange with # of nodes
Source: Trafficware Synchro 8 – Self Designed (Not to Scale)
As mentioned above the numbers with white boxes are the signalized interchanges.
Numbers with blue boxes are nodes (lines connected each other with an angle). Except the
nodes 23, 15, 21 & 42 are un-signalized intersection with yield signs.
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Below design shows the level of service on the intersections.
Exhibit 26 – Displaced Left Interchange with LOS
Source: Synchro 8 (Self-designed - Not to Scale) (Volume data - Courtesy of Victor Vargas, TxDOT)
As per the data provided by TxDOT the volumes were inputted and the results are as
shown in exhibit 24. Level of service U refers to an un-signalized intersection where yield
sign, stop signs are used.
Methodology:
Lengths were measured off of the existing design in San Marcos, TX. Using those
lengths this design was modeled.
Then have the volume data entered, courtesy of Victor Vargas, TxDOT. Implemented
to the design.
Initially the level of service was different for every intersection. Then for the errors
and warnings of coding and fixed all those errors, then LOS dropped down to C.
After making some alterations for intersection cycle lengths and intersection offsets,
simulation process started working fine without any errors
By tweaking the signal timings it helped me to achieve the Level of Service at least B.
There was nothing I could possibly make it A. When I was trying to make level of
service A, every other intersection was getting altered.
One intersection has level of service B in exhibit 26. I tried making it A in many
possible ways but because of the SB thru and WB thru volumes it couldn’t be possible
to attain level of service A for that intersection.
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4.4. Modified Single Point Interchange Analysis:
The interchange in the attached exhibit 25 is also known as Three-point interchange.
Compared to other 2 designs above this design was pretty easy because of the SPUI design
already present in the sample designs in Trafficware.
Exhibit 27 – Synchro Model for Modified Single Point Interchange
Source: Trafficware Synchro 8 – Self Designed (Not to Scale)
It is the altered design of Single Point Urban Interchange (SPUI). There are 3 - 2Φ
signal. I tried providing 100% green for NB and SB thru, but the design simulation turns
unusual. The analysis was conducted for the volume data provided (Courtesy of Crawford
Murphy & Tilly Inc., MO). Detailed report of synchro analysis is attached in the appendix part
of the report.
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Below is the exhibit showing the number of nodes present in the design.
Exhibit 28 – Modified Single Point Interchange with # of nodes
Source: Trafficware Synchro 8 – Self Designed (Not to Scale)
As I mentioned above the numbers with white boxes are the signalized intersections.
Numbers with blue boxes are nodes (line connecting each other with an angle).
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Below exhibit showing the modified single point interchange with the level of service wherein
the volume data were inputted.
Exhibit 29 – Modified Single Point Interchange with LOS
Source: Synchro 8 (Self-designed - Not to Scale) (Volume data - Courtesy of Crawford, Murphy & Tilly, MO)
The 3 intersections with level of service A is doing very well and the locations with
level of service U refers to the node, that is ramps and freeway connecting at that point.
Methodology:
First of all I mentioned this design was altered Single point urban interchange, only
modification from single point is that there are just 2 center ramps in this design as in
the Exhibit 29.
Took the length of the arterial in the existing design of MO-141 at I-55, Arnold, MO.
Implemented those lengths to the synchro model to achieve following intersections in
both Northbound and Southbound.
Then comes the volume data for the model, as by the courtesy of Crawford, Murphy &
Tilly, MO. Volumes were entered.
The level of service for all three intersections was initially C, then I optimized the
intersection cycle lengths and intersection offsets to achieve B.
Although wasn’t happy with it later I tweaked the signal timings a little which really
helped me to achieve LOS A as Exhibit 29 explains it all.
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Appendix - Table of Contents
Sl. No. Description Pg. No.
1.1 Time space diagram for CFLI 35
1.1.1 Results 37
1.1.2 Conclusions 39
1.2 Time space diagram for DLTI 40
1.2.1 Results 42
1.2.2 Conclusions 44
1.3 Time space diagram for MSPI 45
1.3.1 Results 46
1.3.2 Conclusions 48
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Appendix - Table of Exhibits
# of
Exhibit
Design Description
Pg.
No.
Exhibit 30
CFLI
Time space diagram for intersection 1 35
Exhibit 31 Time space diagram for intersection 2 36
Exhibit 32 Time space diagram for intersection 27 36
Exhibit 33 Time space diagram for intersection 28 37
Exhibit 34 Intersection summary for intersection 1 37
Exhibit 35 Signal timing for intersection 1 37
Exhibit 36 Intersection summary for intersection 2 38
Exhibit 37 Signal timing for intersection 2 38
Exhibit 38 Intersection summary for intersection 27 38
Exhibit 39 Signal timing for intersection 27 38
Exhibit 40 Intersection summary for intersection 28 39
Exhibit 41 Signal timing for intersection 28 39
Exhibit 42
DLTI
Time space diagram for intersection 32 40
Exhibit 43 Time space diagram for intersection 34 40
Exhibit 44 Time space diagram for intersection 36 41
Exhibit 45 Time space diagram for intersection 44 41
Exhibit 46 Intersection summary for intersection 32 42
Exhibit 47 Signal timing for intersection 32 42
Exhibit 48 Intersection summary for intersection 34 42
Exhibit 49 Signal timing for intersection 34 43
Exhibit 50 Intersection summary for intersection 36 43
Exhibit 51 Signal timing for intersection 36 43
Exhibit 52 Intersection summary for intersection 44 43
Exhibit 53 Signal timing for intersection 44 43
Exhibit 54
MSPI
Time space diagram for intersection 1 45
Exhibit 55 Time space diagram for intersection 2 45
Exhibit 56 Time space diagram for intersection 9 46
Exhibit 57 Intersection summary for intersection 1 46
Exhibit 58 Signal timing for intersection 1 47
Exhibit 59 Intersection summary for intersection 2 47
Exhibit 60 Signal timing for intersection 2 47
Exhibit 61 Intersection summary for intersection 9 47
Exhibit 62 Signal timing for intersection 9 47
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Appendix
The part of the report consists of software analysis. This section is concerned about
design recommendations for future implementation. The results are attached to this part of the
report. The report is found with respect to the nodes used in Exhibit 21, 24 & 27 in chapter 4.
Appendix consists of these studies below
Time space diagram for different intersections
Results
Conclusions
Time Space Diagrams for Selected Designs:
1.1. Contraflow Left Interchange: (CFLI)
The intersections are mainly divided into two types one is signalized and other is un-
signalized intersection our focus is on the signalized intersections. This design has 6
intersections, but considering only the main intersections for the exhibits. As shown in above
exhibit 22 the intersections are numbered, following those numbers the time space diagram
will be attached below. The numbers for the intersections mentioned are in the exhibit 22
Exhibit 30 – Time Space Diagram for intersection 1
Source: Self Designed CFLI model (Synchro 8)
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Exhibit 31 – Time Space Diagram for intersection 2
Source: Self Designed CFLI model (Synchro 8)
Exhibit 32 – Time Space Diagram for intersection 27
Source: Self Designed CFLI model (Synchro 8)
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Exhibit 33 – Time Space Diagram for intersection 28
Source: Self Designed CFLI model (Synchro 8)
1.1.1. Results:
Implementing the volume data provided by Florida department of transportation did
simulation.
The level of service was not that decent. I believe it’s because of the 3-phase signal on
either side of the bridge making the intersection delay higher.
Simulation was done for various volumes like larger and smaller volumes. I got good
output for the simulation done for the smaller numbers but not the other one.
a. Intersection Summary: Intersection 1
Exhibit 34 – Intersection 1 summary from the synchro report
Source: Synchro 8
b. Signal Timing:
Exhibit 35 – Signal timing for intersection 1
Source: Synchro 8
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a. Intersection Summary: Intersection 2
Exhibit 36 – Intersection 2 summary from the synchro report
Source: Synchro 8
b. Signal Timing:
Exhibit 37 – Signal timing for intersection 2
Source: Synchro 8
a. Intersection Summary: Intersection 27
Exhibit 38 – Intersection 27 summary from the synchro report
Source: Synchro 8
b. Signal Timing:
Exhibit 39 – Signal timing for intersection 27
Source: Synchro 8
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a. Intersection Summary: Intersection 28
Exhibit 40 – Intersection 27 summary from the synchro report
Source: Synchro 8
b. Signal Timing:
Exhibit 41 – Signal timing for intersection 28
Source: Synchro 8
1.1.2. Conclusion:
As discussed in the introduction part this design has cons more than the pros.
The negative part of the design is that it is hard to coordinate a 3-phase signal to
improve the progression.
Eventually if the signals are coordinated, it is a nightmare for the design if there is
moderate to heavy left turn volume from the ramps
It is suitable for the location where the left turns from the ramps are low to moderate.
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1.2. Displaced Left Turn Interchange: (DLTI)
In this design there are 10 signalized intersections. Attached are only the main
intersections time space diagrams as noted, the number for an intersection is shown in the
exhibits above i.e. exhibit 25.
Exhibit 42 – Time space diagram for intersection 32
Source: Synchro 8
Exhibit 43 – Time space diagram for intersection 34
Source: Synchro 8
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Exhibit 44 – Time space diagram for intersection 36
Source: Synchro 8
Exhibit 45 – Time space diagram for intersection 44
Source: Synchro 8
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1.2.1. Results:
The volume data provided by TxDOT were implemented for the simulation and when
the simulation is done the output was expected.
Then the variety of different volumes were assumed and entered it worked well with
the smaller numbers, but found really bad level of service for the larger ones.
Below attached are some summaries of the intersection with signal timings. The
numbers for the intersections were taken from the exhibit 25.
a. Intersection Summary: Intersection 32
Exhibit 46 – Intersection 32 summary from the synchro report
Source: Synchro 8
b. Signal Timing:
Exhibit 47 – Signal timing for intersection 32
Source: Synchro 8
a. Intersection Summary: Intersection 34
Exhibit 48 – Intersection 32 summary from the synchro report
Source: Synchro 8
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b. Signal Timing:
Exhibit 49 – Signal timing for intersection 34
Source: Synchro 8
a. Intersection Summary: Intersection 36
Exhibit 50 – Intersection 36 summary from the synchro report
Source: Synchro 8
b. Signal Timing:
Exhibit 51 – Signal timing for intersection 36
Source: Synchro 8
a. Intersection Summary: Intersection 44
Exhibit 52 – Intersection 44 summary from the synchro report
Source: Synchro 8
b. Signal Timing:
Exhibit 53 – Signal timing for intersection 44
Source: Synchro 8
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1.2.2. Conclusion:
The limitations of synchro when the intersections are placed very near to one another
it is not counted as an intersection
Since it has to maintained 100ft. minimum between 2 intersections that makes the
design worse while simulating.
The design does not entertain moderate to heavy left turns from the ramps. Because of
the problem mentioned above.
It is perfectly suitable for the design where the ramps left turn has low to moderate
volume.
SPACE INTENTIONALLY LEFT BLANK
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1.3. Modified Single Point Interchange: (MSPI)
There are 3 intersections in a row in this design as shown above in the exhibit 28 the
number with the white boxes are intersections. Time space diagram is prepared for those
three intersections are as follow by the number on it.
Exhibit 54 – Time Space Diagram for intersection 1.
Source: Self Designed MSPI model (Synchro 8)
This is the time space diagram for the intersection that is numbered as 1 in the exhibit 28.
Exhibit 55 – Time Space Diagram for intersection 2.
Source: Self Designed MSPI model (Synchro 8)
This is the time space diagram for the intersection 2 as shown in the exhibit 28.
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Exhibit 56 – Time Space Diagram for intersection 9.
Source: Self Designed MSPI model (Synchro 8)
This is the time space diagram for the intersection 9 shown in the exhibit 28.
1.3.1. Results for MSPI:
The design was simulated for the volume data provided by the agency from Missouri
and also simulated for variety of volume data like larger numbers and smaller
numbers.
For every volume this design responds better than other 2 designs mentioned above.
This design is a noble recommendation. After all the data provided is not precise for
larger and smaller numbers but the level of service turned out pretty decent.
Existing condition level of service is A below attached are the exhibits showing the
intersection summary with the level of service and signal timing.
a. Intersection Summary: Intersection 1
Exhibit 57 – Intersection 1 summary from the synchro report
Source: Synchro 8
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b. Signal Timing:
Exhibit 58 – Signal timing for intersection 1
Source: Synchro 8
a. Intersection Summary: Intersection 2
Exhibit 59 – Intersection 2 summary from synchro report
Source: Synchro 8
b. Signal Timing:
Exhibit 60 – Signal timing for intersection 2
Source: Synchro 8
a. Intersection Summary: Intersection 9
Exhibit 61 – Intersection 9 summary from synchro report
Source: Synchro 8
b. Signal Timing:
Exhibit 62 - Signal timing for intersection 9
Source: Synchro 8
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1.3.2. Conclusion:
When the 3 intersections are coordinated with all the movements achieving level of
service A is very easy.
In exhibit 29, NB and SB (intersection 2 & intersection 1 respectively) thru movement
should have 100% green.
If the roads were aligned in a skew angle my recommendation would be this design,
works better with heavy off ramp left turn, moderate to heavy thru and on ramp left
turn on the arterial.
If the roads cross at 90’, think about the actual dollar value for the construction
because it needs large bridge to carry left turning ramps, which is expensive. But no
loss of implementing this design if it is worth it.
Over the other 2 designs this design takes 1st
place for the any future consideration.
SPACE INTENTIONALLY LEFT BLANK
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References:
www.wikipedia.com for some of the terminology referred the website.
“Alternative Intersection/Interchange Information Report” (AIIR) from Federal
Highway Administration.
FHWA Publication No.: FHWA-HRT-09-056, Principal Investigators Warren Hughes
and Ram Jagannathan
“Unconventional Alternative Intersection/Interchange Designs” by GITBOOKS
“Operational Performance of Urban Interchanges with a Large Skew: A comparison of
Diamond, Single-Point & Modified Single-Point Interchanges” by Brian Eads, MO
“Alternate Intersection Analysis” by Klotz Associates, Inc. TX for TxDOT
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