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.
The attached powerpoint contains information about road user characteristics, especially during driving. This PPT will be very much helpful for students studying Road User Characteristics in CE6006 - Traffic Engineering and Management as an elective under affiliated institutions of Anna University.
The attached powerpoint contains information about road user characteristics, especially during driving. This PPT will be very much helpful for students studying Road User Characteristics in CE6006 - Traffic Engineering and Management as an elective under affiliated institutions of Anna University.
A highway pavement is a structure consisting of superimposed layers of processed materials above the natural soil sub-grade, whose primary function is to distribute the applied vehicle loads to the sub-grade. The pavement structure should be able to provide a surface of acceptable riding quality, adequate skid resistance, favorable light reflecting characteristics, and low noise pollution. The ultimate aim is to ensure that the transmitted stresses due to wheel load are sufficiently reduced, so that they will not exceed bearing capacity of the sub-grade. Two types of pavements are generally recognized as serving this purpose, namely flexible pavements and rigid pavements.
Get an overview of pavement types, layers, and their functions, and pavement failures as Improper design of pavements leads to early failure of pavements affecting the riding quality.
Pavements form the basic supporting structure in highway transportation. Each layer of pavement has a multitude of functions to perform which has to be duly considered during the design process. Different types of pavements can be adopted depending upon the traffic requirements.
A highway pavement is a structure consisting of superimposed layers of processed materials above the natural soil sub-grade, whose primary function is to distribute the applied vehicle loads to the sub-grade. The pavement structure should be able to provide a surface of acceptable riding quality, adequate skid resistance, favorable light reflecting characteristics, and low noise pollution. The ultimate aim is to ensure that the transmitted stresses due to wheel load are sufficiently reduced, so that they will not exceed bearing capacity of the sub-grade. Two types of pavements are generally recognized as serving this purpose, namely flexible pavements and rigid pavements.
Get an overview of pavement types, layers, and their functions, and pavement failures as Improper design of pavements leads to early failure of pavements affecting the riding quality.
Pavements form the basic supporting structure in highway transportation. Each layer of pavement has a multitude of functions to perform which has to be duly considered during the design process. Different types of pavements can be adopted depending upon the traffic requirements.
Establishment of any new development generates additional trips that may have negative effects on the existing traffic network. To assess the impact of the development traffic on the transport network and to identify reasonable solutions Traffic Impact Assessment (TIA) is performed. In the absence of sophisticated travel demand model TIA is carried out manually. In manual process, total trip generated from the development site is estimated by multiplying the trip rate with the development size. In this process the task can be completed very easily, but the accuracy of the calculation depends on the reliability of the trip rates used in the calculation. As Bangladesh does not have standard trip rates, TIA is generally performed by using trip rates obtained from the Institute of Transportation Engineers’ “Trip Generation” report, which is ideal for Western countries. In this research, trip rates of shopping centers in Dhaka city are estimated.This study conducts only for trip attraction rates of shopping centers having different sizes and located at different places (Dhanmondi, Gulshan and Siddheswari) in Dhaka city. In order to do so number of persons and vehicles entering the shopping centers in every fifteen minutes interval during peak periods are counted then converted for an hour. From the survey data, it is found that the trip attraction rates of small shopping centers are much higher than that of medium size shopping centers. Macroscopic model is also developed from the survey data. The macroscopic modelrelates the attraction rates of the shopping centers as a function of the physical features such as gross floor area, number of car parking, number of shops and availability of restaurants(available or not) in the shopping centers.
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
Capacity & Level of Service: Highways & Signalized Intersections (Indo-HCM)Vijai Krishnan V
This presentation gives a glimpse on estimating the capacity and Level of Service (LOS) of highway midblock sections and signalized intersections under heterogeneous traffic conditions using the Indo-HCM 2017 Manual. It also compares the Indo-HCM LOS estimation methods with US-HCM. Some practice questions are also included.
I acknowledge the co-author Ms. Sethulakshmi G (Ph. D. Scholar, NIT Surathkal) for her valuable contribution to this presentation.
Operatioal analysis of any road is necessary for its design,planning and implementation procedure.This article mostly deals with preliminary proposal of two lane road of eastern region of Nepal.due to increased traffic condition servicabilty and level of service of koshi higway is found to be very poor hence Dharan submetropolitan city's part is analysed.
Presentation delivered at the 2015 Transportation Association of Canada (TAC) Conference & Exhibition, from September 27 to 30, during the session entitled Goods Movement - Reaching Destinations Safely and Efficiently.
Prepared by
François Bélisle, Eng., B. Sc., M.A.
Marilyne Brosseau, Eng., M.Eng.
Steve Careau, Eng.
Philippe Mytofir, techn.
Validated by:
Stephan Kellner, Eng., M.Eng.
Similar to Freeway & Highway LOS (Transportation Engineering) (20)
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
4. CEE320
Winter2006
Freeway Defined
• A divided highway with full control of
access and two or more lanes for the
exclusive use of traffic in each direction.
• Assumptions
– No interaction with adjacent facilities (streets,
other freeways)
– Free-flow conditions exist on either side of the
facility being analyzed
– Outside the influence or ramps and weaving areas
6. CEE320
Winter2006
Definitions
• Freeway Capacity
– The maximum sustained 15-min flow rate,
expressed in passenger cars per hour per lane,
that can be accommodated by a uniform freeway
segment under prevailing traffic and roadway
conditions in one direction of flow.
7. CEE320
Winter2006
Definitions – Flow Characteristics
• Undersaturated
– Traffic flow that is unaffected by upstream or downstream
conditions.
• Queue discharge
– Traffic flow that has just passed through a bottleneck and is
accelerating back to the FFS of the freeway.
• Oversaturated
– Traffic flow that is influenced
by the effects of a
downstream bottleneck.
From Highway Capacity Manual, 2000
10. CEE320
Winter2006
Definitions – Free-Flow Speed
• Free-Flow Speed (FFS)
– The mean speed of passenger cars that can be
accommodated under low to moderate flow rates on a
uniform freeway segment under prevailing roadway and
traffic conditions.
• Factors affecting free-flow speed
– Lane width
– Lateral clearance
– Number of lanes
– Interchange density
– Geometric design
11. CEE320
Winter2006
Definitions
• Passenger car equivalents
– Trucks and RVs behave differently
– Baseline is a freeway with all passenger cars
– Traffic is expressed in passenger cars per lane per hour
(pc/ln/hr or pcplph)
• Driver population
– Non-commuters suck more at driving
– They may affect capacity
• Capacity
– Corresponds to LOS E and v/c = 1.0
12. CEE320
Winter2006
Definitions – Level of Service (LOS)
• Chief measure of “quality of service”
– Describes operational conditions within a traffic
stream.
– Does not include safety
– Different measures for different facilities
• Six measures (A through F)
• Freeway LOS
– Based on traffic density
13. CEE320
Winter2006
Levels of Service
• LOS A
– Free-flow operation
• LOS B
– Reasonably free flow
– Ability to maneuver is only
slightly restricted
– Effects of minor incidents still
easily absorbed
FromHighwayCapacityManual,2000
14. CEE320
Winter2006
Levels of Service
• LOS C
– Speeds at or near FFS
– Freedom to maneuver is
noticeably restricted
– Queues may form behind any
significant blockage.
• LOS D
– Speeds decline slightly with
increasing flows
– Density increases more quickly
– Freedom to maneuver is more
noticeably limited
– Minor incidents create queuing
FromHighwayCapacityManual,2000
15. CEE320
Winter2006
Levels of Service
• LOS E
– Operation near or at capacity
– No usable gaps in the traffic
stream
– Operations extremely volatile
– Any disruption causes queuing
• LOS F
– Breakdown in flow
– Queues form behind
breakdown points
– Demand > capacity
FromHighwayCapacityManual,2000
17. CEE320
Winter2006
LOS Calculation
• Does not consider
– Special lanes reserved for a particular type of vehicle
(HOV, truck, climbing, etc.)
– Extended bridge and tunnel segments
– Segments near a toll plaza
– Facilities with FFS < 55 mi/h or > 75 mi/h
– Demand conditions in excess of capacity
– Influence of downstream blockages or queuing
– Posted speed limit
– Extent of police enforcement
– Intelligent transportation system features
– Capacity-enhancing effects of ramp metering
Freeway LOS
18. Input
Geometric Data
Measured FFS or BFFS
Volume
BFFS Adjustment
Lane width
Number of lanes
Interchange density
Lateral clearance
Volume Adjustment
PHF
Number of lanes
Driver population
Heavy vehicles
Compute FFS Compute flow rate
Define speed-flow curve
Determine speed using speed-flow curve
Compute density using flow rate and speed
Determine LOS
BFFS Input
Measured
FFS Input
Freeway LOS
20. CEE320
Winter2006
Determining FFS
• Measure FFS in the field
– Low to moderate traffic conditions
• Use a baseline and adjust it (BFFS)
IDNLCLW ffffBFFSFFS −−−−=
FFS = free-flow speed (mph)
BFFS = base free-flow speed, 70 mph (urban), 75 mph (rural)
fLW = adjustment for lane width (mph)
fLC = adjustment for right-shoulder lateral clearance (mph)
fN = adjustment for number of lanes (mph)
fID = adjustment for interchange density (mph)
Freeway LOS
21. CEE320
Winter2006
Lane Width Adjustment (fLW)
• Base condition (fLW = 0)
– Average width of 12 ft. or wider across all lanes
From Highway Capacity Manual, 2000
Freeway LOS
22. CEE320
Winter2006
Lateral Clearance Adjustment (fLC)
• Base condition (fLC = 0)
– 6 ft. or greater on right side
– 2 ft. or greater on the median or left side
From Highway Capacity Manual, 2000
Freeway LOS
23. CEE320
Winter2006
Number of Lanes Adjustment (fN)
• Base condition (fN = 0)
– 5 or more lanes in one direction
– Do not include HOV lanes
– fN = 0 for all rural freeway segments
From Highway Capacity Manual, 2000
Freeway LOS
24. CEE320
Winter2006
Interchange Density Adjustment (fIC)
• Base condition (fIC = 0)
– 0.5 interchanges per mile (2-mile spacing)
– Interchange defined as having at least one on-ramp
– Determined over 6-mile segment
From Highway Capacity Manual, 2000
Freeway LOS
25. CEE320
Winter2006
Determining Flow Rate
• Adjust hourly volumes to get pc/ln/hr
pHV
p
ffNPHF
V
v
×××
=
vp = 15-minute passenger-car equivalent flow rate (pcphpl)
V = hourly volume (veh/hr)
PHF = peak hour factor
N = number of lanes in one direction
fHV = heavy-vehicle adjustment factor
fP = driver population adjustment factor
Freeway LOS
26. CEE320
Winter2006
Peak Hour Factor (PHF)
• Typical values
– 0.80 to 0.95
– Lower PHF characteristic or rural or off-peak
– Higher PHF typical of urban peak-hour
415 ×
=
V
V
PHF
V = hourly volume (veh/hr) for hour of analysis
V15 = maxiumum 15-min. flow rate within hour of analysis
4 = Number of 15-min. periods per hour
Freeway LOS
27. CEE320
Winter2006
Heavy Vehicle Adjustment (fHV)
• Base condition (fHV = 1.0)
– No heavy vehicles
– Heavy vehicle = trucks, buses, RVs
• Two-step process
– Determine passenger-car equivalents (ET)
– Determine fHV
Freeway LOS
28. CEE320
Winter2006
Passenger-Car Equivalents (ET)
• Extended segments method
– Determine the type of terrain and select ET
– No one grade of 3% or more is longer than 0.25 miles
OR
– No one grade of less than 3% is longer than 0.5 miles
From Highway Capacity Manual, 2000
Freeway LOS
29. CEE320
Winter2006
Passenger-Car Equivalents (ET)
• Specific grades method
– Any grade of 3% or more that is longer than 0.25 miles
OR
– Any grade of less than 3% that is longer than 0.5 miles
From Highway Capacity Manual, 2000
Freeway LOS
32. CEE320
Winter2006
Passenger-Car Equivalents (ET)
• Composite grades method
– Determines the effect of a series of steep
grades in succession
– Method OK if…
• All subsection grades are less than 4%
OR
• Total length of composite grade is less than 4000 ft.
– Otherwise, use a detailed technique in the
Highway Capacity Manual (HCM)
From Highway Capacity Manual, 2000
Freeway LOS
33. CEE320
Winter2006
Determine fHV
( ) ( )111
1
−+−+
=
RRTT
HV
EPEP
f
fHV = Heavy vehicle adjustment factor
ET, ER = Passenger-car equivalents for trucks/buses and RVs
PT, PR = Proportion of trucks/buses and RVs in traffic stream
Freeway LOS
34. CEE320
Winter2006
Driver Population Adjustment (fP)
• Base condition (fP = 1.0)
– Most drivers are familiar with the route
• Commuter drivers
– Typical values between 0.85 and 1.00
• Two-step process
– Determine passenger-car equivalents (ET)
– Determine fHV
Freeway LOS
36. CEE320
Winter2006
Determine Average PC Speed (S)
Use vp and FFS curve to find average passenger car speed (S)
From Highway Capacity Manual, 2000
Freeway LOS
37. CEE320
Winter2006
Determine Average PC Speed (S)
For 70 < FFS ≤ 75 mph AND (3400 – 30FFS) < vp ≤ 2400
For 55 < FFS ≤ 70 mph AND (3400 – 30FFS) < vp ≤ (1700 + 10FFS)
For 55 < FFS ≤ 75 mph AND vp < (3400 – 30FFS)
−
−+
−−=
6.2
100030
340030
3
160
FFS
FFSv
FFSFFSS
p
( )
−
−+
−−=
6.2
170040
340030
3407
9
1
FFS
FFSv
FFSFFSS
p
FFSS =
Freeway LOS
40. CEE320
Winter2006
Example
Geometry
• 11 ft. lane width
• Left lateral clearance = 5 ft.
• Right lateral clearance = 4 ft.
Other
• 7 am PHF = 0.95
• 10 pm PHF = 0.99
• 2% trucks
• 3% buses
Determine the typical LOS for SR 520 eastbound near Microsoft
(MP 10.25 – shown in the picture below) at 7 a.m. and 10 p.m.
from WSDOT’s SRWeb
http://srview.wsdot.wa.gov/
Freeway LOS
45. CEE320
Winter2006
At 7am the ½ hour volume is about 4000 veh/hr
At 10 pm the ½ hour volume is about 1700 veh/hr
Graph from the Puget Sound Regional Council’s Puget Sound Trends, No. T6, July 1997
Determine Flow Rate (vp)
Freeway LOS
51. CEE320
Winter2006
Base Conditions for Multilane Highway
• Level terrain, with grades no greater than 2 percent
• Minimum lane width = 12 ft
• Objects no closer than 6 ft from the edge of the traveled
pavement (at the roadside or median)
• No direct access points along the roadway
• Divided highway
• Traffic stream composed entirely of passenger cars
• Free flow speed of 60 mph or more
• Driver population composed principally of regular users
Multilane Highway LOS
52. CEE320
Winter2006
Free Flow Speed (FFS)
• Measure FFS in the field
– Low to moderate traffic conditions
• Use a baseline and adjust it (BFFS)
AMLCLW ffffBFFSFFS −−−−=
FFS = free-flow speed (mph)
BFFS = base free-flow speed, 60 mph is typically used
fLW = adjustment for lane width (mph)
fLC = adjustment for right-shoulder lateral clearance (mph)
fM = adjustment for median type (mph)
fA = adjustment for access points (mph)
Multilane Highway LOS
53. CEE320
Winter2006
Lane Width Adjustment (fLW)
• Base condition (fLW = 0)
– Average width of 12 ft. or wider across all lanes
From Highway Capacity Manual, 2000
Multilane Highway LOS
Same as Freeway LOS
54. CEE320
Winter2006
Lateral Clearance Adjustment (fLC)
• Base condition (fLC = 0)
– 12 ft or greater TLC
• LCL = 6 ft for undivided highways
– (accounted for in median type adjustment)
• LCL = 6 ft for two-way left-turn lanes
FromHighwayCapacityManual,2000
Multilane Highway LOS
LR LCLCTLC +=
56. CEE320
Winter2006
Access-Point Density Adjustment (fA)
• For each access point/mi FFS decreases by 0.25 mph
• Base condition (fA = 0)
– 0 access points per mile
• For NAPM ≤ 40: fA = 0.25 × NAPM
• For NAPM > 40: fA = 10
From Highway Capacity Manual, 2000
Multilane Highway LOS
57. CEE320
Winter2006
Determining Flow Rate
• Adjust hourly volumes to get pc/ln/hr
pHV
p
ffNPHF
V
v
×××
=
vp = 15-minute passenger-car equivalent flow rate (pcphpl)
V = hourly volume (veh/hr)
PHF = peak hour factor
N = number of lanes in one direction
fHV = heavy-vehicle adjustment factor
fP = driver population adjustment factor
Multilane Highway LOS
Same as Freeway LOS
58. CEE320
Winter2006
Heavy Vehicle Adjustment (fHV)
• Base condition (fHV = 1.0)
– No heavy vehicles
– Heavy vehicle = trucks, buses, RVs
• Two-step process
– Determine passenger-car equivalents (ET)
– Determine fHV
Same as Freeway LOS
Multilane Highway LOS
59. CEE320
Winter2006
Passenger-Car Equivalents (ET)
• Extended segments method
– Determine the type of terrain and select ET
– No one grade of 3% or more is longer than 0.5 miles
OR
– No one grade of less than 3% is longer than 1 mile
From Highway Capacity Manual, 2000
Multilane Highway LOS
60. CEE320
Winter2006
Passenger-Car Equivalents (ET)
• Specific grades method
– Any grade of 3% or more that is longer than 0.5 miles
OR
– Any grade of less than 3% that is longer than 1 mile
From Highway Capacity Manual, 2000
Multilane Highway LOS
63. CEE320
Winter2006
Passenger-Car Equivalents (ET)
• Composite grades method
– Determines the effect of a series of steep
grades in succession
– Method OK if…
• All subsection grades are less than 4%
OR
• Total length of composite grade is less than 4000 ft.
– Otherwise, use a detailed technique in the
Highway Capacity Manual (HCM)
From Highway Capacity Manual, 2000
Same as Freeway LOS
Multilane Highway LOS
64. CEE320
Winter2006
Determine fHV
( ) ( )111
1
−+−+
=
RRTT
HV
EPEP
f
fHV = Heavy vehicle adjustment factor
ET, ER = Passenger-car equivalents for trucks/buses and RVs
PT, PR = Proportion of trucks/buses and RVs in traffic stream
Multilane Highway LOS
Same as Freeway LOS
65. CEE320
Winter2006
Driver Population Adjustment (fP)
• Base condition (fP = 1.0)
– Most drivers are familiar with the route
• Commuter drivers
– Typical values between 0.85 and 1.00
Same as Freeway LOS
Multilane Highway LOS
66. CEE320
Winter2006
Determine Average PC Speed (S)
Use vp and FFS curve to find average passenger car speed (S)
From Highway Capacity Manual, 2000
Multilane Highway LOS
67. CEE320
Winter2006
Determine Average PC Speed (S)
For 55 < FFS ≤ 60 mph AND vp > 1400
For 50 < FFS ≤ 55 mph AND vp > 1400
For 55 < FFS ≤ 75 mph AND vp < (3400 – 30FFS)
For vp < 1400
−
−
−−=
31.1
88028
1400
13
10
3
FFS
v
FFSFFSS
p
−
−
−−=
31.1
1181
5
171
1400
41
219
205
34
FFS
v
FFSFFSS
p
FFSS =
−
−
−−=
31.1
112036
1400
9
56
5
1
FFS
v
FFSFFSS
p
Multilane Highway LOS
73. CEE320
Winter2006
Definitions
• Annual average daily traffic (AADT)
– Annual traffic averaged on a daily basis
• Design hourly volume (DHV)
– Traffic volume used for design calculations
– Typically between the 10th
and 50th
highest volume hour
of the year (30th
highest is most common)
• K-factor
– Relationship between AADT and DHV
AADT
DHV
K =
74. CEE320
Winter2006
Definitions
• Directional distribution factor (D)
– Factor reflecting the proportion of peak-hour traffic
traveling in the peak direction
– Often there is much more traffic in one direction than
the other
• Directional design-hour volume (DDHV)
AADTDKDDHV ××=
77. CEE320
Winter2006
Primary References
• Mannering, F.L.; Kilareski, W.P. and Washburn, S.S. (2005).
Principles of Highway Engineering and Traffic Analysis, Third Edition.
Chapter 6
• Transportation Research Board. (2000). Highway Capacity Manual
2000. National Research Council, Washington, D.C.
Editor's Notes
Lots of measurements in the top part, a few in the queue part and a few in the congested part
Segment 1 = top part = uncongested
Segment 2 = straight part = queue discharge
Segment 3 = bottom part = within a queue
Measured from the edge of the paved shoulder to the nearest edge of the traveled lane
No adjustments for left side
3 miles upstream and 3 miles downstream
You measure or are given V
3 miles upstream and 3 miles downstream
Level = any combo of alignments permitting heavy vehicles to maintain approximately the same speed as passenger cars. Generally includes short grades of no more than 2%
Rolling = causes heavy vehicles to reduce speed substantially below passenger cars but does not cause them to operate at their limiting speed for the given terrain for any significant length of time or at frequent intervals
Mountainous = causes heavy vehicles to operate at their limiting speed for significant distances or at frequent intervals
No RVs for downgrades
No RVs for downgrades
Interpolation is OK
75 mph is dashed because is was extrapolated from the 70 mph curve
Interpolation is OK
75 mph is dashed because is was extrapolated from the 70 mph curve
Usually you can easily tell from the graph but it’s a good idea to check here
Density defines LOS!
FFS = BFFS – fLW – fLC – fN – fID
Assume BFFS is 70 mph for urban freeway
fLW = 1.9
fLC = 0.8 (do we use 2 or 3 lanes in one direction?) use 3 – this determines speed
FFS = BFFS – fLW – fLC – fN – fID
Assume BFFS is 70 mph for urban freeway
fLW = 1.9
fLC = 0.8 (do we use 2 or 3 lanes in one direction?) use 3 – this determines speed
fN = 4.5 (do not include the HOV lane)
IC density = 5/6 = 0.833 interchanges/mile
Interpolating from the table we get 1.68
½ hour volume is for both directions
Therefore the 1-hour volume in one direction is the same because there are 4 lanes total (2 in each direction)
ET = 1.5
Assume there are no RVs
fHV = 1/(1+PT(ET-1) + PR(ER-1)
fHV = 1/(1+0.05(1.5-1) + 0(1.2-1) = 0.9756
Assume commuters, therefore fP = 1.00
Vp = 4000 vph / (0.95)(2)(0.9756)(1.00) = 2158 pcplph
FFS = 61.1 mph
Vp = 2158 pcplph
S = about 56 mph
Looks like LOS E
Density = 2158/56 = 38.5 pc/mi/ln
Density = 2158/56 = 38.5 pc/mi/ln
LOS E at 7am
At 10 pm
Vp = 1700/(0.99)(2)(0.9756)(1.00) = 880 pc/ln/hr
S = 61.1 mph (still in free-flow area)
D = 880/61.1 = 14.4 pc/mi/ln
LOS B
Measured from the edge of the paved shoulder to the nearest edge of the traveled lane
No adjustments for left side
3 miles upstream and 3 miles downstream
You measure or are given V
3 miles upstream and 3 miles downstream
Level = any combo of alignments permitting heavy vehicles to maintain approximately the same speed as passenger cars. Generally includes short grades of no more than 2%
Rolling = causes heavy vehicles to reduce speed substantially below passenger cars but does not cause them to operate at their limiting speed for the given terrain for any significant length of time or at frequent intervals
Mountainous = causes heavy vehicles to operate at their limiting speed for significant distances or at frequent intervals
No RVs for downgrades
No RVs for downgrades
Interpolation is OK
75 mph is dashed because is was extrapolated from the 70 mph curve
Interpolation is OK
75 mph is dashed because is was extrapolated from the 70 mph curve
Usually you can easily tell from the graph but it’s a good idea to check here
Density defines LOS!