Incorporating Travel Time Reliability into the Highway Capacity Manual

Zegeer, John; Bonneson, James A; Dowling, Richard; Ryus, Paul; Vandehey, Mark; Kittelson, Wayne; Rouphail, Nagui M.; Schroeder, Bastian J; Hajbabaie, Ali; Aghdashi, Behzad; Chase, Thomas E.; Sajjadi, Soheil; Margiotta, Richard; Elefteriadou, Lily

doi:10.17226/22487

Cited by 11 publications

(7 citation statements)

References 13 publications

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“…In contrast to the FDOT application of reliability, which examines freeways and arterials system wide, this work focuses on the analysis of individual segments consistent with the HCM definitions. The SHRP 2-L08 project considered non-recurring congestion effects, such as weather, incidents, work zones, and special events (Kittelson et al 2013). Regarding freeways, the different weather conditions pertain to rain (low, medium, and high level similar to the 2010HCM categorization), snow (light, medium, and high level), visibility (low, minimum), cold, fog, and normal weather.…”

Section: Travel Time Reliabilitymentioning

confidence: 99%

Quantifying weather impacts on traffic operations for implementation into a travel time reliability model

Elefteriadou

Kondyli

2016

Transportation Letters

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Travel time reliability allows agencies to evaluate the performance of a facility beyond the peak hour, and to consider operations over a longer period of time considering non-recurring events, such as incidents and adverse weather. The Florida Department of Transportation (FDOT) has incorporated travel time reliability as a primary mobility performance measure. This paper details the method developed for addressing the effects of weather on travel time, as well as its implementation on travel time reliability estimation for state-wide reporting in Florida. To account for Florida-specific conditions, weather impacts focus only on rain intensity. The methodology incorporates different rainfall characteristics of regions across Florida and calibrates the rainfall intensity distribution models on a zip code basis for each hour. The probability of clear weather, light rain, and heavy rain is determined for each hour and then applied to the respective freeway or arterial section based on its zip code.

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Section: Travel Time Reliabilitymentioning

confidence: 99%

Quantifying weather impacts on traffic operations for implementation into a travel time reliability model

Elefteriadou

Kondyli

2016

Transportation Letters

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“…Here, a calendar year is selected as the period based on which the bottlenecks are identified and monitored. Such use of calendar year is a common practice in transportation planning and in other research fields ( 14 ).…”

Section: Methodsmentioning

confidence: 99%

Characteristics and Temporal Stability of Recurring Bottlenecks

Ahmed

Rouphail

Tanvir

2018

Transportation Research Record

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This study applies and updates a method which identifies and quantifies the extent of traffic congestion from recurring freeway bottlenecks. Additionally, the spatiotemporal stability of bottlenecks over an extended period was tested. Over time congestion at bottlenecks may increase, may decrease, or may migrate to other nearby locations. Analysis of stability is important since prioritizing and applying treatments at bottlenecks is a multiyear process. In addition, a robust method for selecting sensitivity based parameters to identify and quantify bottleneck effects is presented. Subsequently, a systematic framework is developed for tracking and archiving the spatiotemporal changes in the recurring bottlenecks. The proposed method is demonstrated on a case study on Interstate 40 in North Carolina using three years of probe data. A congestion speed ratio detection threshold of 0.7 and a probability of activation threshold of 33% for the study area were determined from a sensitivity test to ascertain their recurrence. The method identified 13 bottlenecks with their impacts ranging from 35 to 3,278 mi-hours of congestion per year. Eight bottlenecks either newly emerged or had their queues merged or shifted between successive years. Even spatially stable bottlenecks had significant variation in their activation frequency and queue length. Exploration of the changes in bottleneck severity and locations revealed the influence of a long-term work zone in the area and the effect of the rapid growth in traffic demand. Local agencies can use this method to shortlist recurring bottlenecks and track changes to plan mitigation strategies.

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“…The truck footprint and speed-acceleration profiles were specified in the vehicle models as were their acceleration and deceleration functions in the VISSIM simulation based on the truck fleet characteristics analysis performed by the NCFRP 41 research team (2). The team developed truck acceleration profiles (acceleration versus speed) for two truck classes, single-unit trucks (FHWA Vehicle Class 5) and semitrailer and combination trucks (FHWA Vehicle Class 9), based on the NCHRP Report 505 (6) and other sources (7).…”

Section: Simulation Development Stepsmentioning

confidence: 99%

“…This research effort looked into the synergistic effects of trucks and grades together to determine if the effects are significant and therefore should be included in the estimation of saturation flow rates at signals. This work is part of a National Cooperative Freight Research Program Project 41 (NCFRP 41): Incorporating Truck Analysis in the Highway Capacity Manual (2).…”

mentioning

confidence: 99%

Developing Improved Truck Passenger Car Equivalent Values at Signalized Intersections

Skabardonis

Dowling²,

Kiattikomol

et al. 2014

Transportation Research Record

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This paper describes the methodology and findings for developing improved passenger car equivalent (PCE) factors for trucks at signalized intersections on the basis of field data and simulation modeling. The Highway Capacity Manual 2010 (HCM 2010) assumes a single PCE value of 2.00 for trucks at traffic signals. The proposed truck PCE values are sensitive to the proportion of trucks, truck type, and intersection's approach grade. It is recommended that the current HCM 2010 approach of computing the heavy vehicle and grade effects on saturation flow rates independently be replaced with a new combined heavy vehicle and grade adjustment factor that takes into account the synergistic effects of heavy vehicles combined with upgrades.

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Incorporating Travel Time Reliability into the Highway Capacity Manual

Cited by 11 publications

References 13 publications

Quantifying weather impacts on traffic operations for implementation into a travel time reliability model

Quantifying weather impacts on traffic operations for implementation into a travel time reliability model

Characteristics and Temporal Stability of Recurring Bottlenecks

Developing Improved Truck Passenger Car Equivalent Values at Signalized Intersections

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