This document discusses measuring traffic flow characteristics at mid-block sections. It begins with an introduction to traffic system objectives like travel time reduction and safety. It then describes procedures for measuring traffic flow using point measurements, short section measurements, and a moving observer method. Key traffic flow variables are defined including flow, density, speed, headway and spacing. Fundamental relationships between these variables are presented, as well as traffic flow models like Greenshield's model.
Lecture 02 Traffic Flow Characteristics (Traffic Engineering هندسة المرور & D...Hossam Shafiq I
This document provides information about a traffic engineering course, including contact details for the instructor, how to access the course website, and an overview of some key topics that will be covered in the course, such as time-space diagrams, headway and gap, vehicle arrival patterns, and the Poisson and exponential distributions as they relate to modeling traffic flow. Examples are provided for how to use the Poisson and shifted exponential distributions to calculate probabilities related to time headways. The document also discusses challenges with using the exponential distribution to model real-world traffic, introduces the concept of a chi-square test for comparing observed vs expected distributions, and provides an example chi-square calculation to test whether observed headway data fits an exponential distribution. It concludes
Traffic volume is a fundamental measure of traffic on a road system, measured as the number of vehicles crossing a section of road per unit time. It is used for various purposes like planning, design, and traffic management. There are manual and automatic methods to count traffic volume. Manual methods involve field observers counting and classifying vehicles in different time intervals, while automatic methods use technologies like pneumatic tubes buried in roads, inductive loops in pavements, and radar to detect vehicle presence and count traffic volume without human observers. The collected data is then analyzed to produce traffic flow maps, intersection diagrams, and trend charts to understand traffic patterns and inform transportation planning.
The document defines different types of traffic volumes used for transportation planning and design. Daily volumes like average annual daily traffic (AADT) are used to establish trends over time. Hourly volumes like the peak hour volume are most important for design and operational analysis. Within the peak hour, the peak 15-minute volume and peak hour factor (PHF) account for fluctuations in flow. Sub-hourly volumes below 15 minutes are also sometimes analyzed.
Detailed description of Capacity and Level of service of Multi lane highways based on Highway Capacity Manual (HCM2010) along with one example for finding LOS of a highway
The document discusses a traffic volume study conducted at Russell Square in Dhaka. It defines key terms like average daily traffic (ADT) and level of service (LOS). Data was collected manually over three hours and analyzed to find a service flow rate of 1,131 passenger car units per hour, indicating an LOS of D. The average daily traffic was calculated as 16,080 passenger cars with an annual average of 22,432. Traffic movement was found to be nearly equal in both directions.
1. The document discusses various methods for conducting traffic volume studies, including manual counts, mechanical counters, and automatic counts.
2. Manual counts involve people standing at the roadside and recording vehicle information on tally sheets or mechanical/electronic counting boards.
3. Automatic counts use sensors like pneumatic tubes, inductive loops, weigh-in-motion scales, radar detectors, and video cameras to collect traffic data without human observation.
03 Traffic Stream Characteristics (Traffic Engineering هندسة المرور & Prof. S...Hossam Shafiq I
This document outlines the topics and objectives for CE 436 Traffic Engineering taught by Prof. Saad AlGadhi at King Saud University. The course will cover traffic stream characteristics including microscopic parameters like headways and spacing, and macroscopic parameters like flow, speed, and density. It will discuss the relationships between these parameters and introduce common traffic flow models. Homework assignments include problems analyzing speed-flow-density relationships and applying the hydrodynamic traffic flow theory.
Lecture 02 Traffic Flow Characteristics (Traffic Engineering هندسة المرور & D...Hossam Shafiq I
This document provides information about a traffic engineering course, including contact details for the instructor, how to access the course website, and an overview of some key topics that will be covered in the course, such as time-space diagrams, headway and gap, vehicle arrival patterns, and the Poisson and exponential distributions as they relate to modeling traffic flow. Examples are provided for how to use the Poisson and shifted exponential distributions to calculate probabilities related to time headways. The document also discusses challenges with using the exponential distribution to model real-world traffic, introduces the concept of a chi-square test for comparing observed vs expected distributions, and provides an example chi-square calculation to test whether observed headway data fits an exponential distribution. It concludes
Traffic volume is a fundamental measure of traffic on a road system, measured as the number of vehicles crossing a section of road per unit time. It is used for various purposes like planning, design, and traffic management. There are manual and automatic methods to count traffic volume. Manual methods involve field observers counting and classifying vehicles in different time intervals, while automatic methods use technologies like pneumatic tubes buried in roads, inductive loops in pavements, and radar to detect vehicle presence and count traffic volume without human observers. The collected data is then analyzed to produce traffic flow maps, intersection diagrams, and trend charts to understand traffic patterns and inform transportation planning.
The document defines different types of traffic volumes used for transportation planning and design. Daily volumes like average annual daily traffic (AADT) are used to establish trends over time. Hourly volumes like the peak hour volume are most important for design and operational analysis. Within the peak hour, the peak 15-minute volume and peak hour factor (PHF) account for fluctuations in flow. Sub-hourly volumes below 15 minutes are also sometimes analyzed.
Detailed description of Capacity and Level of service of Multi lane highways based on Highway Capacity Manual (HCM2010) along with one example for finding LOS of a highway
The document discusses a traffic volume study conducted at Russell Square in Dhaka. It defines key terms like average daily traffic (ADT) and level of service (LOS). Data was collected manually over three hours and analyzed to find a service flow rate of 1,131 passenger car units per hour, indicating an LOS of D. The average daily traffic was calculated as 16,080 passenger cars with an annual average of 22,432. Traffic movement was found to be nearly equal in both directions.
1. The document discusses various methods for conducting traffic volume studies, including manual counts, mechanical counters, and automatic counts.
2. Manual counts involve people standing at the roadside and recording vehicle information on tally sheets or mechanical/electronic counting boards.
3. Automatic counts use sensors like pneumatic tubes, inductive loops, weigh-in-motion scales, radar detectors, and video cameras to collect traffic data without human observation.
03 Traffic Stream Characteristics (Traffic Engineering هندسة المرور & Prof. S...Hossam Shafiq I
This document outlines the topics and objectives for CE 436 Traffic Engineering taught by Prof. Saad AlGadhi at King Saud University. The course will cover traffic stream characteristics including microscopic parameters like headways and spacing, and macroscopic parameters like flow, speed, and density. It will discuss the relationships between these parameters and introduce common traffic flow models. Homework assignments include problems analyzing speed-flow-density relationships and applying the hydrodynamic traffic flow theory.
This document discusses capacity analysis and level of service for transportation facilities. It defines capacity as the maximum hourly rate of vehicles that can pass a point under prevailing conditions. Level of service is a qualitative measure of operational conditions within a traffic stream. The Highway Capacity Manual procedures are reviewed for calculating capacity for basic freeway sections and multilane highways. Key factors that influence capacity estimates include free flow speed, lane width, lateral clearance, access points, and presence of heavy vehicles.
The AASHTO guide for designing rigid pavements considers several factors: the effective modulus of subgrade reaction, concrete elastic modulus and modulus of rupture, load transfer coefficient, reliability and standard deviation, traffic load application, and serviceability loss. The document then proceeds to describe the process for determining each of these factors to complete the pavement thickness design using design charts.
Traffic studies are carried out to analyze traffic characteristics and help decide geometric design and traffic control measures. The main traffic studies include traffic volume, speed, origin-destination, traffic flow characteristics, capacity, and accident studies. Traffic volume studies measure the number of vehicles on a road section over time and are used for planning, operations, and analysis. Speed studies measure the speeds of vehicles using methods like short-distance timing or radar guns.
This document discusses different types of traffic speed studies including spot speed studies, travel time studies, and speed delay studies. It then provides details on specific objectives, scope, and methods of conducting traffic speed studies. The document presents data from a traffic speed study conducted at two intersections in Dhaka, including spot speeds, histograms, frequency and cumulative frequency curves. It analyzes the data to determine weighted average speed, pace, modal speed and compares time mean speed to space mean speed based on the Wardrop relationship. Finally, it calculates delay time, value of travel time and vehicle operating costs.
Design Considerations for AASHTO Flexible pavement designImran Nawaz
The document discusses the key factors considered in AASHTO flexible pavement design: pavement performance, traffic, roadbed soils, materials of construction, environment, drainage, and reliability. Pavement performance is measured by present serviceability index (PSI) on a scale of 0 to 5. Traffic is considered in terms of estimated single axle loads (ESALs). Roadbed soils are characterized by properties like CBR, R-value, and resilient modulus (Mr). Materials are assigned structural numbers (SN) based on properties. Drainage and environment affect Mr. Reliability ensures the design survives the design life with a given level of probability. The design process involves determining layer SNs from properties then thickness to achieve a
Pavement refers to durable surface materials laid down on areas for vehicular or foot traffic like roads and walkways. There are two main types: flexible pavement made of materials like asphalt, and rigid pavement made of concrete. Flexible pavement has lower initial costs but requires more maintenance, while rigid pavement has higher initial costs but lasts longer with less maintenance. The document discusses the layers, materials, design processes, and testing methods used for both flexible and rigid pavements.
Freeway & Highway LOS (Transportation Engineering)Hossam Shafiq I
This document discusses methods for determining freeway and highway level of service (LOS). It defines key terms like free-flow speed, passenger car equivalents, and LOS criteria. The document outlines how to calculate the free-flow speed by measuring it or using a baseline adjusted for factors like lane width. It also explains how to determine the traffic flow rate and convert volumes to passenger cars per lane per hour. Finally, it shows how to use the speed-flow curve and density to establish the LOS for a basic freeway segment based on traffic conditions.
Intelligent Transportation Systems (Transportation Engineering)Hossam Shafiq I
This document discusses intelligent transportation systems (ITS) as a way to more efficiently utilize existing transportation infrastructure. It outlines the main components of ITS, including advanced traffic management systems which use technologies like traffic cameras and variable message signs to monitor and manage traffic flow. Advanced traveler information systems provide real-time traffic and road condition information to drivers. The document also discusses advanced public transportation systems and commercial vehicle operations that use technologies to improve transportation system performance and safety. In summary, the document introduces intelligent transportation systems as an alternative to costly new construction that uses technologies to maximize existing infrastructure capacity.
Here are the key steps and calculations for the homework:
1. Use design speed of 55 mph, emax of 4%, and fmax of 0.12 from Green Book
2. Calculate minimum radius using formula: Rmin = V2/(15(e+f)) = 1,200 ft
3. Select radius of 1,400 ft
4. Given: PI station of 352+44.97, Δ of 35° 24' 55"
5. Calculate curve length using L = ΔR/5729.58 = 1,260 ft
6. Calculate tangent length using T = Rtan(Δ/2) = 630 ft
7. Calculate PC station: PC = PI - T
This document defines microscopic traffic stream parameters such as speed, density, flow, time headway, space headway, and spacing. It establishes the relationships between these parameters and provides the basic traffic flow equation relating flow, density, and speed. Examples are also given to demonstrate calculating traffic flow parameters from given data.
Geometric Design - Horizontal and vertical curvessachin dass
The document discusses key aspects of highway geometric design including horizontal and vertical alignment. It covers topics such as superelevation design, centrifugal force effects, transition curves, extra widening for curves, and vertical curve types. The key points are:
- Superelevation is used to counteract centrifugal force when negotiating curves, and its design considers factors like design speed, radius of curve, and coefficient of friction.
- Transition curves are used between tangents and circular curves to gradually change curvature and introduce superelevation for driver comfort.
- Extra widening is required for curves to accommodate off-tracking of vehicles and driver tendencies, calculated based on number of lanes, wheel base, design
The document discusses the design of a flexible pavement for a proposed 25 km expressway from Bandar A to Bandar B. It provides information on the differences between flexible and rigid pavements. It then outlines the traffic data and estimated traffic loads for the expressway of 3.9 million ESALs over 10 years. Resilient modulus values are provided for the pavement layers. Using the AASHTO design method and chart, structural numbers are calculated for three subgrade resilient modulus scenarios. The pavement thicknesses are then determined, with the asphalt layer being 5.5 inches, base layer 8 inches, and subgrade layer 10 inches.
This document summarizes different techniques for assigning routes in transportation network modeling. It describes the all-or-nothing assignment method, direction curve method, capacity restraint assignment techniques, and multi-route assignment technique. For each method, it provides details on the approach, limitations, and examples of models that use the technique. The document is presented by five students as part of their course on urban transportation systems.
The document provides information on highway geometric design elements. It discusses road cross section elements such as the right-of-way, carriageway, shoulders, median, crown slope, side slopes, curbs, and drainage ditches. It also covers geometric design controls and criteria including functional classification, terrain, traffic volume and composition, design vehicle, and design speed. Finally, it discusses elements of geometric design like sight distance, horizontal alignment including tangents and circular curves, and vertical alignment.
The Benkelman beam is the simplest and the oldest deflection
test device, developed in the United States in the mid-1950s. Its used to measure the structural capacity of a flexible pavement.
8 capacity-analysis ( Transportation and Traffic Engineering Dr. Sheriff El-B...Hossam Shafiq I
This document discusses concepts related to transportation capacity analysis including:
- Definitions of level of service (LOS) categories A through F and their characteristics.
- How capacity is defined as the maximum hourly rate of vehicles that can pass a point under prevailing conditions.
- Procedures from the Highway Capacity Manual (HCM) for calculating capacity for basic freeway sections and the impacts of factors like lane width, lateral clearance, and free flow speed.
- The relationships between capacity, LOS, and transportation design and how capacity analysis can inform design.
Capacity & Level of Service: Highways & Signalized Intersections (Indo-HCM)Vijai Krishnan V
The document discusses capacity and level of service analysis for highways and signalized intersections using the Indian Highway Capacity Manual (Indo-HCM) methodology. It provides an overview of the Indo-HCM framework, compares it to the US Highway Capacity Manual, and presents step-by-step calculations for determining the capacity and level of service of highways using the Indo-HCM approach. A sample problem is also included to demonstrate the application of the Indo-HCM methodology.
This document provides an overview of traffic engineering, including its definition, scope, and key areas of focus. Traffic engineering is a branch of civil engineering that deals with the safe and efficient movement of people and goods on roadways. It involves the study of traffic characteristics, operations, planning and analysis, geometric design, administration and management, and road safety. Some key aspects covered include traffic flow parameters like speed, volume, and density; vehicle characteristics; and methods for conducting traffic studies to analyze volume, speed, accidents, and other metrics. The goal of traffic engineering is to achieve efficient traffic flow with the lowest number of accidents.
This document discusses assessing the pavement condition and estimating the current asset value of a 6 lane-km road stretch in Karachi, Pakistan. Key steps included identifying distresses, calculating Pavement Condition Index scores for sections of the road, and determining an overall PCI of 77, indicating a satisfactory condition. Current asset value was estimated at 7.7 million using the road's initial value of 10 million and PCI score. The road needs only small maintenance to address some poorer sections.
Rotaries are intersections where traffic moves in one direction around a central island. They convert severe conflicts into milder merging and diverging movements. Some advantages are lower speeds, fewer accidents, and self-regulation without signals. Rotaries are suitable for moderate traffic volumes up to 3000 vehicles/hour and work best when traffic from all approaches is balanced. Their capacity depends on entry/exit widths, weaving width and length, and proportion of weaving traffic.
Lec 12 Capacity Analysis (Transportation Engineering Dr.Lina Shbeeb)Hossam Shafiq I
This document discusses various concepts in transportation engineering related to traffic flow theory and capacity analysis. It provides definitions and examples of key terms including:
- Average daily traffic and peak hour factors which are used to determine directional design hourly volume
- Applications of traffic flow theory such as determining turning lane lengths and delays
- Level of service which is a qualitative measure of operational conditions within a traffic stream
- Capacity, which is the maximum hourly rate of vehicles that can reasonably pass a point under prevailing conditions
- Methods for calculating capacity and adjusting for factors like lane width, lateral clearance, and heavy vehicles using equations from the Highway Capacity Manual.
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
This document discusses capacity analysis and level of service for transportation facilities. It defines capacity as the maximum hourly rate of vehicles that can pass a point under prevailing conditions. Level of service is a qualitative measure of operational conditions within a traffic stream. The Highway Capacity Manual procedures are reviewed for calculating capacity for basic freeway sections and multilane highways. Key factors that influence capacity estimates include free flow speed, lane width, lateral clearance, access points, and presence of heavy vehicles.
The AASHTO guide for designing rigid pavements considers several factors: the effective modulus of subgrade reaction, concrete elastic modulus and modulus of rupture, load transfer coefficient, reliability and standard deviation, traffic load application, and serviceability loss. The document then proceeds to describe the process for determining each of these factors to complete the pavement thickness design using design charts.
Traffic studies are carried out to analyze traffic characteristics and help decide geometric design and traffic control measures. The main traffic studies include traffic volume, speed, origin-destination, traffic flow characteristics, capacity, and accident studies. Traffic volume studies measure the number of vehicles on a road section over time and are used for planning, operations, and analysis. Speed studies measure the speeds of vehicles using methods like short-distance timing or radar guns.
This document discusses different types of traffic speed studies including spot speed studies, travel time studies, and speed delay studies. It then provides details on specific objectives, scope, and methods of conducting traffic speed studies. The document presents data from a traffic speed study conducted at two intersections in Dhaka, including spot speeds, histograms, frequency and cumulative frequency curves. It analyzes the data to determine weighted average speed, pace, modal speed and compares time mean speed to space mean speed based on the Wardrop relationship. Finally, it calculates delay time, value of travel time and vehicle operating costs.
Design Considerations for AASHTO Flexible pavement designImran Nawaz
The document discusses the key factors considered in AASHTO flexible pavement design: pavement performance, traffic, roadbed soils, materials of construction, environment, drainage, and reliability. Pavement performance is measured by present serviceability index (PSI) on a scale of 0 to 5. Traffic is considered in terms of estimated single axle loads (ESALs). Roadbed soils are characterized by properties like CBR, R-value, and resilient modulus (Mr). Materials are assigned structural numbers (SN) based on properties. Drainage and environment affect Mr. Reliability ensures the design survives the design life with a given level of probability. The design process involves determining layer SNs from properties then thickness to achieve a
Pavement refers to durable surface materials laid down on areas for vehicular or foot traffic like roads and walkways. There are two main types: flexible pavement made of materials like asphalt, and rigid pavement made of concrete. Flexible pavement has lower initial costs but requires more maintenance, while rigid pavement has higher initial costs but lasts longer with less maintenance. The document discusses the layers, materials, design processes, and testing methods used for both flexible and rigid pavements.
Freeway & Highway LOS (Transportation Engineering)Hossam Shafiq I
This document discusses methods for determining freeway and highway level of service (LOS). It defines key terms like free-flow speed, passenger car equivalents, and LOS criteria. The document outlines how to calculate the free-flow speed by measuring it or using a baseline adjusted for factors like lane width. It also explains how to determine the traffic flow rate and convert volumes to passenger cars per lane per hour. Finally, it shows how to use the speed-flow curve and density to establish the LOS for a basic freeway segment based on traffic conditions.
Intelligent Transportation Systems (Transportation Engineering)Hossam Shafiq I
This document discusses intelligent transportation systems (ITS) as a way to more efficiently utilize existing transportation infrastructure. It outlines the main components of ITS, including advanced traffic management systems which use technologies like traffic cameras and variable message signs to monitor and manage traffic flow. Advanced traveler information systems provide real-time traffic and road condition information to drivers. The document also discusses advanced public transportation systems and commercial vehicle operations that use technologies to improve transportation system performance and safety. In summary, the document introduces intelligent transportation systems as an alternative to costly new construction that uses technologies to maximize existing infrastructure capacity.
Here are the key steps and calculations for the homework:
1. Use design speed of 55 mph, emax of 4%, and fmax of 0.12 from Green Book
2. Calculate minimum radius using formula: Rmin = V2/(15(e+f)) = 1,200 ft
3. Select radius of 1,400 ft
4. Given: PI station of 352+44.97, Δ of 35° 24' 55"
5. Calculate curve length using L = ΔR/5729.58 = 1,260 ft
6. Calculate tangent length using T = Rtan(Δ/2) = 630 ft
7. Calculate PC station: PC = PI - T
This document defines microscopic traffic stream parameters such as speed, density, flow, time headway, space headway, and spacing. It establishes the relationships between these parameters and provides the basic traffic flow equation relating flow, density, and speed. Examples are also given to demonstrate calculating traffic flow parameters from given data.
Geometric Design - Horizontal and vertical curvessachin dass
The document discusses key aspects of highway geometric design including horizontal and vertical alignment. It covers topics such as superelevation design, centrifugal force effects, transition curves, extra widening for curves, and vertical curve types. The key points are:
- Superelevation is used to counteract centrifugal force when negotiating curves, and its design considers factors like design speed, radius of curve, and coefficient of friction.
- Transition curves are used between tangents and circular curves to gradually change curvature and introduce superelevation for driver comfort.
- Extra widening is required for curves to accommodate off-tracking of vehicles and driver tendencies, calculated based on number of lanes, wheel base, design
The document discusses the design of a flexible pavement for a proposed 25 km expressway from Bandar A to Bandar B. It provides information on the differences between flexible and rigid pavements. It then outlines the traffic data and estimated traffic loads for the expressway of 3.9 million ESALs over 10 years. Resilient modulus values are provided for the pavement layers. Using the AASHTO design method and chart, structural numbers are calculated for three subgrade resilient modulus scenarios. The pavement thicknesses are then determined, with the asphalt layer being 5.5 inches, base layer 8 inches, and subgrade layer 10 inches.
This document summarizes different techniques for assigning routes in transportation network modeling. It describes the all-or-nothing assignment method, direction curve method, capacity restraint assignment techniques, and multi-route assignment technique. For each method, it provides details on the approach, limitations, and examples of models that use the technique. The document is presented by five students as part of their course on urban transportation systems.
The document provides information on highway geometric design elements. It discusses road cross section elements such as the right-of-way, carriageway, shoulders, median, crown slope, side slopes, curbs, and drainage ditches. It also covers geometric design controls and criteria including functional classification, terrain, traffic volume and composition, design vehicle, and design speed. Finally, it discusses elements of geometric design like sight distance, horizontal alignment including tangents and circular curves, and vertical alignment.
The Benkelman beam is the simplest and the oldest deflection
test device, developed in the United States in the mid-1950s. Its used to measure the structural capacity of a flexible pavement.
8 capacity-analysis ( Transportation and Traffic Engineering Dr. Sheriff El-B...Hossam Shafiq I
This document discusses concepts related to transportation capacity analysis including:
- Definitions of level of service (LOS) categories A through F and their characteristics.
- How capacity is defined as the maximum hourly rate of vehicles that can pass a point under prevailing conditions.
- Procedures from the Highway Capacity Manual (HCM) for calculating capacity for basic freeway sections and the impacts of factors like lane width, lateral clearance, and free flow speed.
- The relationships between capacity, LOS, and transportation design and how capacity analysis can inform design.
Capacity & Level of Service: Highways & Signalized Intersections (Indo-HCM)Vijai Krishnan V
The document discusses capacity and level of service analysis for highways and signalized intersections using the Indian Highway Capacity Manual (Indo-HCM) methodology. It provides an overview of the Indo-HCM framework, compares it to the US Highway Capacity Manual, and presents step-by-step calculations for determining the capacity and level of service of highways using the Indo-HCM approach. A sample problem is also included to demonstrate the application of the Indo-HCM methodology.
This document provides an overview of traffic engineering, including its definition, scope, and key areas of focus. Traffic engineering is a branch of civil engineering that deals with the safe and efficient movement of people and goods on roadways. It involves the study of traffic characteristics, operations, planning and analysis, geometric design, administration and management, and road safety. Some key aspects covered include traffic flow parameters like speed, volume, and density; vehicle characteristics; and methods for conducting traffic studies to analyze volume, speed, accidents, and other metrics. The goal of traffic engineering is to achieve efficient traffic flow with the lowest number of accidents.
This document discusses assessing the pavement condition and estimating the current asset value of a 6 lane-km road stretch in Karachi, Pakistan. Key steps included identifying distresses, calculating Pavement Condition Index scores for sections of the road, and determining an overall PCI of 77, indicating a satisfactory condition. Current asset value was estimated at 7.7 million using the road's initial value of 10 million and PCI score. The road needs only small maintenance to address some poorer sections.
Rotaries are intersections where traffic moves in one direction around a central island. They convert severe conflicts into milder merging and diverging movements. Some advantages are lower speeds, fewer accidents, and self-regulation without signals. Rotaries are suitable for moderate traffic volumes up to 3000 vehicles/hour and work best when traffic from all approaches is balanced. Their capacity depends on entry/exit widths, weaving width and length, and proportion of weaving traffic.
Lec 12 Capacity Analysis (Transportation Engineering Dr.Lina Shbeeb)Hossam Shafiq I
This document discusses various concepts in transportation engineering related to traffic flow theory and capacity analysis. It provides definitions and examples of key terms including:
- Average daily traffic and peak hour factors which are used to determine directional design hourly volume
- Applications of traffic flow theory such as determining turning lane lengths and delays
- Level of service which is a qualitative measure of operational conditions within a traffic stream
- Capacity, which is the maximum hourly rate of vehicles that can reasonably pass a point under prevailing conditions
- Methods for calculating capacity and adjusting for factors like lane width, lateral clearance, and heavy vehicles using equations from the Highway Capacity Manual.
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
This document provides an overview of a traffic engineering course. The objectives are to provide insight into traffic components and factors, explain how to conduct and analyze various traffic surveys, illustrate how to apply statistical tools to traffic data, and provide insight into traffic regulations and control devices. The outcomes are for students to be able to describe traffic characteristics, conduct and analyze surveys, apply statistical tools, and classify regulations and design control devices. The syllabus covers traffic characteristics like components, user characteristics, maneuvers, and stream characteristics. It defines stream parameters like volume, density, headway, and speed.
This document summarizes a study of traffic flow characteristics for heterogeneous traffic in India. Speed, flow, and time headway data were collected from a six-lane urban road and analyzed. Headways between different vehicle combinations were found to best fit several statistical distributions. Speed-flow curves were plotted to determine the speed at which optimal flow occurs, though the study was limited by only using one hour of data. The results provide insight into modeling headways and understanding traffic flow in heterogeneous, mixed traffic conditions.
This document provides an overview of traffic engineering studies and concepts related to an exit exam tutorial. It discusses topics like traffic flow elements, flow-density relationships, highway capacity, level of service, traffic control devices, and traffic signal systems. It also provides sample questions related to traffic flow modeling concepts developed by Greenshields and Greenberg, as well as questions about traffic volume studies, characteristics of traffic like average daily traffic and peak hour volume, and vehicle classification.
This document describes the process for analyzing and determining the level of service of weaving, merging, and diverging segments on highways. It involves 8 steps: 1) collecting input data, 2) determining flow rates, 3) determining the configuration, 4) calculating maximum weaving length, 5) determining capacity, 6) calculating total lane changing, 7) determining average speed, and 8) calculating density to determine the LOS. An example problem is also provided to demonstrate applying the 8-step process to analyze a weaving segment on an urban freeway.
1) The document tracks changes over 20 years to the traffic service quality in downtown Fort Worth using the Two-Fluid model. It calibrates the model for 1990 and 2012 to compare the Two-Fluid parameters (Tm, n) over time.
2) Key network attributes like block length, number of lanes, and signal timing were also compared between 1990 and 2012. Changes to these attributes help explain changes to the Two-Fluid parameters.
3) The results show certain attributes like the fraction of one-way streets and signal density are major factors in determining traffic service quality as represented by the Two-Fluid parameters. Comparing the 1990 and 2012 calibrations indicates how the downtown network
This document discusses a traffic analysis project on Gomti Nagar in Lucknow, India with respect to pedestrian facilities. It provides background on traffic studies and their purpose in evaluating transportation systems. It also outlines different types of traffic counts and analysis methods, including manual counts, cordon counts, screen line counts, intersection counts, and pedestrian counts. The document describes the project timeline and concludes that future transportation investments in the area must be strategically coordinated with land use plans to maximize benefits.
This document describes a traffic analysis project on Gomti Nagar in Lucknow, India with respect to pedestrian facilities. It provides background on traffic studies and their purpose of evaluating transportation systems. It also outlines different types of traffic counts and analysis methods that were used in the project, including manual counts, intersection counts, and periodic volume counts. The document discusses the findings of the traffic analysis and provides recommendations for improving pedestrian facilities and widening roads. It includes a PERT chart outlining the timeline and process of the project.
The document discusses platoon dispersion of heterogeneous traffic on a corridor in Chennai, India. Data on platoon sizes and travel times was collected at distances of 200-1400m between intersections under fixed-time signal control. Platoon sizes decreased with distance due to differences in vehicle speeds and interactions. The average travel speed was 46km/hr. Robertson's platoon dispersion model with a smoothing factor of 0.878 provided the best fit to the data. Traffic composition and distances between six intersections on the study corridor are also presented.
Design & Construction of B.I.T. Driveway (As per rural specification)IJERA Editor
The motive of undertaking this project of “Design & Construction of B.I.T. Driveway (As per rural
specification)” is to study and evaluate the performance in real design and working conditions of the rural road
flexible pavement with IRC:37-2001 and IRC:SP:20-2002. In this paper, the work is carried out to measure the
traffic volume on the top surface of the B.I.T. Driveway. Rural connectivity is taken as one of the major
component in increasing the agricultural output and earning capacity of the rural population. There is a marked
improvement in quality of life by way of better educational facilities, improved health services, improved
attendance by the school teachers as well as students.
This document summarizes a study that used a dual graph representation to simulate urban traffic from both a microscopic and macroscopic perspective. The study represented roads as nodes and intersections as links to form dual graphs of city networks. A traffic model was implemented on these dual graphs to simulate vehicle movement and analyze overall traffic flow patterns. Simulation results showed that regular lattice grid networks performed better than scale-free self-organized networks in terms of overall traffic capacity and individual vehicle traveling times. However, the model could be improved by incorporating more realistic traffic control methods and vehicle navigation strategies.
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.
Designing of a Traffic Signaling System at T-IntersectionIJERA Editor
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This document discusses highway design speed and level of service. It defines design speed as the maximum safe speed for a road based on its geometric design features. Level of service is a qualitative measure of traffic conditions on a roadway, ranging from free-flowing traffic at LOS A to congested traffic at LOS F. The document provides examples of calculating level of service for a highway based on factors like lane width, access points, and traffic volume using methods from the Highway Capacity Manual. It shows how changes to the road design, such as adding lanes or widening lanes, can improve the level of service.
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This document defines key terms used in traffic impact assessments and outlines the typical process for conducting one. It involves identifying the context of the site and surrounding road network, conducting a traffic survey of existing conditions, analyzing peak hour traffic and road capacities, estimating additional traffic from the proposed project, adding that to future traffic projections, and drawing conclusions about impacts and needed mitigation measures. The goal is to understand how a new development will affect the existing transportation system and identify solutions to minimize congestion.
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Measurement of Traffic Flow Characteristics at mid-block sections -Universal Engineering college.ppt
1. MEASUREMENT OF TRAFFIC FLOW
CHARACTERISTICS AT MID-BLOCK SECTIONS
Dr. Shriniwas Arkatkar, Associate Professor, CED, SVNIT
P.G. CENTRE IN TRANSPORTATION ENGG. PLANNING
DEPARTMENT OF CIVIL ENGINEERING
SVNIT, SURAT
2. Outline of the Talk
Introduction
Measurement Procedures
Traffic Flow Characteristics at mid-block
Time space diagram
Fundamental diagram of traffic flow
Traffic flow models
Summary and Points for Discussion
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
2
3. Traffic System Objectives
Travel Time Reduction (Speed)
Reduce Congestion (Increase Efficiency)
Safety
Economy
Mobility
Environmental Effects
Energy Consumption
Equity
Growth
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
3
4. Achieving traffic system objectives:
1. To understand, represent and analyze traffic
flow characteristics under various design and
control parameters
2. Select design and control levels to meet
objectives
Iterative processes….
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
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5. Major Traffic Flow Characteristics
Traffic flow is a time-space phenomenon
Highly non-linear system response
Different Inputs lead to the same output
Same input may lead to different outputs
Complex Interactions
Speed
Acceleration / Deceleration
Lateral placement
Longitudinal position
Conflicting Objectives
Speed differential versus safety
Efficiency versus speed
LOS versus infrastructure utilization
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
5
6. Measurement Procedures
Advancements in Measurement capabilities
Influencing interest in traffic flow analysis
Measurement of Traffic Flow Characteristics at mid-block sections
Measurement at a point
17-Feb-23
6
10. Measurement Procedures..
Measurement of Traffic Flow Characteristics at mid-block sections
Measurement over a length of road Example-2
Km
5.200
Km
5.500
Km
5.700 Km
5.900
5 % Gradient on National
Highway No. 4 near Pune,
Maharashtra
17-Feb-23
10
13. Measurement Procedures..
Measurement of Traffic Flow Characteristics at mid-block sections
Observer moving in the traffic stream
Speed – Time profile
17-Feb-23
13
14. Measurement Procedures..
Measurement of Traffic Flow Characteristics at mid-block sections
Observer moving in the traffic stream
Speed – Distance profile
17-Feb-23
14
15. Measurement Procedures..
Measurement of Traffic Flow Characteristics at mid-block sections
Wide-area samples obtained simultaneously
from a number of vehicles, as part of Intelligent
Transportation Systems (ITS)
17-Feb-23
15
16. Traffic Variables of Interest
Rates of flow (vehicles per unit time);
Speeds (distance per unit time);
Travel time over a known length of road (or sometimes the
inverse of speed, is used);
Occupancy (percent of time a point on the road is occupied
by vehicles);
Density (vehicles per unit distance);
Time headway between vehicles (time per vehicle);
Spacing, or space headway between vehicles (distance
per vehicle);
Concentration (measured by density or occupancy).
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
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17. Data Collection Methods
Probe
vehicle
Tfc
Data
Point
Based
Radar
O-D counts
Loop detectors
enoscope
videographic
Area
Based
Video
Aerial Photography
License plate
Stream
Based
Moving
observer
Floating
car
Two fluid
method
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
17
18. time
space
t T
L
Measurement of Traffic Flow Characteristics at mid-block sections
Time-Space Diagram
Point Measurement
Short Section
Measurement
Measurement
along the road
length
Moving Observer
beyond road length
17-Feb-23
18
19. Microscopic Traffic Variables
Microscopic:
Focuses on elemental unit–individual vehicles
And Interactions with neighbors
Discrete particle model
Decisions of interest:
Overtaking
Lane-changing
Vehicle following
Gap acceptance
Placement
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
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21. Plotting of Grid lines
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
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• Lateral points are of 1m interval
• Longitudinal points are of 5m interval
22. Plotting of Grid lines…
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
22
• Grid lines were plotted in AutoCAD
• Saved as image file
AutoCAD drawing
Image file (.jpg format)
23. Overlaying of Grid
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
23
Overlaying the grid image into video file using Ulead Video Converter
25. Extraction of frames using Irfan View
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
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26. Extracted data in excel sheet
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
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• Noted the coordinates, frame number etc. in excel sheet.
27. 4. Extracted data in excel sheet
• Noted the coordinates, frame number etc. in excel sheet.
• Raw data file: 2. it corridor2. 1st input(example).xlsx
17-Feb-23
27 Measurement of Traffic Flow Characteristics at mid-block sections
28. Time-Space Diagram: Analysis
at a Fixed Position
h1
h2 h4
h3
T time
position
0
0
L
x
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
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29. Time-Space Diagram: Analysis
at a Fixed Time
t
s1
s2
L
0
time
position
t0
Measurement of Traffic Flow Characteristics at mid-block sections
17-Feb-23
29
30. Macroscopic Traffic Variables
Focus on stream characteristics
Aggregation of individual vehicle properties
Applied to model overall stream features such
as congestion, delays approximately.
Computationally easier
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
30
31. Terminologies in Traffic Engineering
1. Density(K): Number of vehicles present in a stated
length of road at an instant. Expressed as
vehicles/unit of length(veh/km)
2. Flow(q): Number of vehicles passing a specified point
during a stated period of time. Expressed as
vehicles/unit of time(veh/hr)
3. Time headway (h): Time interval between the passage
of the fronts of successive vehicles at a specified
point. Measured in seconds.
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
31
32. 4. Space headway(s): Distance between the fronts
of successive vehicles. Measured in meters.
5. Speed(v): Distance travelled per unit time.
6. Spacing(s): The centre to centre distance
between any two consecutive vehicles in motion.
7. Clearance(c) : Distance from end of one vehicle
to the front of other following vehicle.
8. Occupancy : Percentage of time that the
detection zone of the instrument is occupied by a
vehicle.
Measurement of Traffic Flow Characteristics at mid-block sections
Terminologies in Traffic Engineering.
17-Feb-23
32
36. • Speed (v) –m/sec or mph or km/h
• Flow (q) – veh/sec or vph
• Density (k) – veh/ft or vpm or v/km
• Spacing (s) – ft/veh or meter/veh
• Headway (h) – sec/veh
• Clearance (c) – ft/veh or meter/veh
• Gap (g) – sec/veh
Measurement of Traffic Flow Characteristics at mid-block sections
Remember Units are Critical!
17-Feb-23
36
37. Comparison of Micro and Macro
Traffic Flow Characteristics
Microscopic
Time headway – (h)
Spacing –(s)
Speed – (v)
Macroscopic
Volume (Q)
Density (K)
Speed (V)
Time Aggregated
Space Aggregated
17-Feb-23
37
Measurement of Traffic Flow Characteristics at mid-block sections
38. Fundamental Relationships
• q = k v
(veh/hr) = (veh/km) (km/hr)
• h = 1 / q
(sec/veh) = 1 / (veh/hr) (3600)
• s = 1 / k
(m/veh) = 1 / (veh/km) (1000)
What are the assumptions for these relationships?
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
38
39. Assumptions: Traffic Relationships
h and s are constant over entire stretch
h and s are constant over time
h and s are identical across drivers
Under these assumptions v = s/h = Q/K
17-Feb-23
39
Measurement of Traffic Flow Characteristics at mid-block sections
40. Speeds: TMS and SMS
• Time mean speed (TMS): Average of the speed
measurements at one point in space over a
period of time.
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
40
t
x
1 2
3
4
v4
A x x
x x
41. Travel Time Averaged Speed (SMS)
i
i
i
i
i
s
t
V
t
V 1
_
i
i
i
i
i
i
i
i
s
V
l
l
V
l
V
V
l
V
/
/
)
/
(
1
_
i
i
i
i
V
n
V
n
)
/
1
(
1
1
/
1
Harmonic Mean of Speeds = Reciprocal of Arithmetic mean of 1/Speeds
However, if you measure at a single point by say radar and take
harmonic mean, the result may not give space mean speed. Why?
17-Feb-23
41
Measurement of Traffic Flow Characteristics at mid-block sections
42. 17-Feb-23
Measurement of Traffic Flow Characteristics at mid-block sections
42
Travel Time Averaged Speed (SMS)
t
x
1 2
3
4
v4
A x
B
t = T
t = 0
t1
t2
t3
l3
L
i
i
i
i
i
s
t
V
t
V 1
_
3
2
1
3
1
_
t
t
t
l
L
L
V s
43. Instantaneous Space Mean Speed
Suppose you can take a snapshot of all vehicles
in a stretch of a highway at some point in time.
Take the average of speeds of all vehicles in the
snapshot at that instant of time
t
time
of
t
ins
that
at
stretch
that
in
present
vehicles
only
represents
i
Here
n
t
V
V
i
i
s
tan
)
(
2
_
17-Feb-23
43
Measurement of Traffic Flow Characteristics at mid-block sections
44. Instantaneous Space Mean Speed
17-Feb-23
Measurement of Traffic Flow Characteristics at mid-block sections
44
t
x
1 2
3
4
v4
T0
x
x
x
x
45. Estimation of volume and travel time
using moving observer method
Measurement of Traffic Flow Characteristics at mid-block sections
45
17-Feb-23
46. Estimation of Travel time on two-lane road
Measurement of Traffic Flow Characteristics at mid-block sections
46
17-Feb-23
47. Problem (Travel Time)
The following tables give the particulars collected for a
section of road 3.5 km long during the course of a
moving observer study. Calculate the journey speed and
running speed in each direction.
Measurement of Traffic Flow Characteristics at mid-block sections
47
Run
No
Journey Time Stopped
Delay
Overtaking
vehicles
Overtaken
vehicles
Opposite
Direction
Flow
min sec min sec
1 8 32 1 40 4 7 268
2 7 50 1 30 5 5 350
3 8 15 1 10 6 6 390
4 9 28 1 50 4 5 260
Table 1: North-South Direction:
17-Feb-23
48. Traffic Volumes on all routes
Measurement of Traffic Flow Characteristics at mid-block sections
48
17-Feb-23
52. Fundamental Traffic Flow Diagram
17-Feb-23
Measurement of Traffic Flow Characteristics at mid-block sections
52
53. Fundamental Traffic Flow Diagram
17-Feb-23
Measurement of Traffic Flow Characteristics at mid-block sections
53
54. Fundamental diagram of traffic flow
(flow vs. density)
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
54
Flow
(q)
Density (k)
Optimal flow
or capacity,qmax
Optimal
density, ko
Jam density,
kj
Mean free flow speed, uf
Optimal speed, uo
Speed is the
slope. u = q/k
Congested
flow
55. Greenshield’s Model
Assume a linear relationship between v and k:
High Density = Low
Speed
Low Density = High
Speed
vf
kj
k
k
v
v
v
j
f
f
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
55
58. Greenshield’s model
k
k
u
u
u
j
f
f
s
2
k
k
u
k
u
k
u
q
j
f
f
s
Nice characteristics of the Greenshield’s model:
2
f
o
u
u
2
j
o
k
k
4
max
f
ju
k
q
This model works for all k = 0 to k = kj
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
58
60. Example-1
Assuming a linear v-k relationship, the mean free speed
is 60 mph near zero density, and the corresponding jam
density is 140 vpm. Assume the average length of
vehicles is 20 ft. Find:
v(k) and q(k)
Sketch v-k, v-q, and q-k diagrams
Compute v and k at q=1000 vph
Compute the average headway, spacings,
clearances, and gaps when the flow is maximum
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
60
61. Example-2
Given that the relationship between and
density obtained from the actual data is
Estimate all the macroscopic and microscopic
parameters
k
u 24
.
0
5
.
54
Measurement of Traffic Flow Characteristics at mid-block sections 17-Feb-23
61