Urban travel time reliability at different traffic conditions

2017 ◽  
Vol 22 (2) ◽  
pp. 106-120 ◽  
Author(s):  
Fangfang Zheng ◽  
Jie Li ◽  
Henk van Zuylen ◽  
Xiaobo Liu ◽  
Hongtai Yang
2021 ◽  
Author(s):  
Swapneel R. Kodupuganti ◽  
Sonu Mathew ◽  
Srinivas S. Pulugurtha

The rapid growth in population and related demand for travel during the past few decades has had a catalytic effect on traffic congestion, air quality, and safety in many urban areas. Transportation managers and planners have planned for new facilities to cater to the needs of users of alternative modes of transportation (e.g., public transportation, walking, and bicycling) over the next decade. However, there are no widely accepted methods, nor there is enough evidence to justify whether such plans are instrumental in improving mobility of the transportation system. Therefore, this project researches the operational performance of urban roads with heterogeneous traffic conditions to improve the mobility and reliability of people and goods. A 4-mile stretch of the Blue Line light rail transit (LRT) extension, which connects Old Concord Rd and the University of North Carolina at Charlotte’s main campus on N Tryon St in Charlotte, North Carolina, was considered for travel time reliability analysis. The influence of crosswalks, sidewalks, trails, greenways, on-street bicycle lanes, bus/LRT routes and stops/stations, and street network characteristics on travel time reliability were comprehensively considered from a multimodal perspective. Likewise, a 2.5-mile-long section of the Blue Line LRT extension, which connects University City Blvd and Mallard Creek Church Rd on N Tryon St in Charlotte, North Carolina, was considered for simulation-based operational analysis. Vissim traffic simulation software was used to compute and compare delay, queue length, and maximum queue length at nine intersections to evaluate the influence of vehicles, LRT, pedestrians, and bicyclists, individually and/or combined. The statistical significance of variations in travel time reliability were particularly less in the case of links on N Tryon St with the Blue Line LRT extension. However, a decrease in travel time reliability on some links was observed on the parallel route (I-85) and cross-streets. While a decrease in vehicle delay on northbound and southbound approaches of N Tryon St was observed in most cases after the LRT is in operation, the cross-streets of N Tryon St incurred a relatively higher increase in delay after the LRT is in operation. The current pedestrian and bicycling activity levels seemed insignificant to have an influence on vehicle delay at intersections. The methodological approaches from this research can be used to assess the performance of a transportation facility and identify remedial solutions from a multimodal perspective.


2019 ◽  
Vol 27 (4) ◽  
pp. 250-265 ◽  
Author(s):  
Zhen Chen ◽  
Wei Fan

Abstract Travel time reliability (TTR) is an important measure which has been widely used to represent the traffic conditions on freeways. The objective of this study is to develop a systematic approach to analyzing TTR on roadway segments along a corridor. A case study is conducted to illustrate the TTR patterns using vehicle probe data collected on a freeway corridor in Charlotte, North Carolina. A number of influential factors are considered when analyzing TTR, which include, but are not limited to, time of day, day of week, year, and segment location. A time series model is developed and used to predict the TTR. Numerical results clearly indicate the uniqueness of TTR patterns under each case and under different days of week and weather conditions. The research results can provide insightful and objective information on the traffic conditions along freeway segments, and the developed data-driven models can be used to objectively predict the future TTRs, and thus to help transportation planners make informed decisions.


Author(s):  
A. K. M. Abir ◽  
Mark W. Burris ◽  
Clifford Spiegelman

Travelers place value on both time savings and reliability when choosing a route for a trip. The value of travel time (VOT) has long been an integral part of the appraisal of transport projects. Recently, some transport planners have been incorporating the value of travel time reliability (VOR) as well. This research used data generated by automated vehicle identification sensors from Katy Freeway travelers in Houston, Texas, to estimate VOT and VOR based on revealed preferences of these travelers. Lane choice models were developed to examine the factors influencing travelers’ lane choice decisions in different traffic conditions and to estimate their VOT. Models with two independent variables— travel time and toll—resulted in an estimated VOT from $1.96 to $8.06/h for all trips on a monthly basis. The research could not conclude whether the VOR had any impact on travelers’ lane choice decisions. The percentage of managed-lane trips was higher for the those who traveled the whole length of the managed–general-purpose lanes than for those who traveled only a part of the managed–general-purpose lanes. This difference might be the result of easier accessibility at the end of the managed lanes compared with that for midpoints.


2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Mohammad K. H. Shehada ◽  
Alexandra Kondyli

Ramp metering has been found to improve traffic conditions on the freeway mainline by breaking the platoons of ramp vehicles minimizing turbulence at the merge locations. The majority of the ramp metering evaluation studies have examined traffic performance under specific demand conditions, whereas travel time reliability and variability aspects have not been adequately addressed. This paper focuses on evaluating two well-known ramp metering algorithms in terms of travel time reliability as well as other performance measures such as queue lengths, throughput, and congestion duration, looking at a wide range of traffic demands throughout a calendar year. The evaluation was done through simulating an 8-mile corridor in Kansas City, KS. The results showed localized improvements due to ramp metering at the northern section of the facility, in terms of travel time reliability, throughput, and congestion duration. It was also shown that ramp metering may cause a new (possibly “hidden”) bottleneck to occur downstream, thus diluting its overall benefits when looking at an entire freeway facility. It is further noted that although ALINEA performed better than HERO on the mainline, traffic operations on the on-ramps significantly deteriorated using isolated control.


Author(s):  
Qianfei Li ◽  
Jingtao Ma ◽  
Mehrnaz Ghamami ◽  
Yu (Marco) Nie

Author(s):  
Whoibin Chung ◽  
Mohamed Abdel-Aty ◽  
Ho-Chul Park ◽  
Qing Cai ◽  
Mdhasibur Rahman ◽  
...  

A new decision support system (DSS) using travel time reliability was developed for integrated active traffic management (IATM) including freeways and arterials. The DSS consists of recommendation and evaluation of response plans. The DSS also includes three representative traffic management strategies: variable speed limits, queue warning, and ramp metering. The recommendation of response plans for recurring traffic congestion was generated from the logics of the three strategies. The evaluation of response plans was conducted by travel time reliability through the prediction of traffic conditions with response plans. The near-future prediction of traffic conditions with control strategies was conducted through METANET for freeways and arterials. The developed DSS was evaluated under three types of traffic congestion: extreme, heavy, and moderate. According to the evaluation results, the developed DSS recommended an IATM strategy with the highest synergistic relationships in real time and contributed to enhancing the effectiveness of the IATM strategies. It was confirmed that arterials should have the allowable residual capacity for the improvement of traffic flow of the entire corridor network. Furthermore, the DSS demonstrated a more balanced traffic condition between freeways and arterials.


2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Chintan Advani ◽  
Smit Thakkar ◽  
Sachin Shah ◽  
Shriniwas Arkatkar ◽  
Ashish Bhaskar

2020 ◽  
Vol 11 (2) ◽  
pp. 44-55
Author(s):  
Prosper S. Nyaki ◽  
Hannibal Bwire ◽  
Nurdin K. Mushule

AbstractThe assessment of travel time reliability enables precise prediction of travel times, better activity scheduling and decisions for all users of the road network. Furthermore, it helps to monitor traffic flow as a crucial strategy for reducing traffic congestion and ensuring high-quality service in urban roads. Travel time reliability is a useful reference tool for evaluating transport service quality, operating costs and system efficiency. However, many analyses of travel time reliability do not provide true travel variation under heterogeneous traffic flow conditions where traffic flow is a mixture of motorized and non-motorized transport. This study analysed travel time reliability under heterogeneous traffic conditions. The travel reliabilities focused on passenger waiting time at bus stops, in-vehicle travel time, and delay time at intersections which were analysed using buffer time, standard deviation, coefficient of variation, and planning time. The data used were obtained from five main bus routes in Dar es Salaam. The results indicate low service reliability in the outbound directions compared to inbound directions. They also intend to raise awareness of policy-makers about the situation and to make them shift from expanding road networks towards optimising road operations.


2012 ◽  
Vol 166-169 ◽  
pp. 2591-2596
Author(s):  
Shu Ming Fang ◽  
Hiroshi Wakabayashi

Travel time reliability is very important for normal period and abnormal period especially disaster recovery. However, traditional indexes can not reflect travel time reliability in disaster areas. Thus a new travel time reliability index for disaster is proposed in this paper. The index proposed in this paper is different from usual indexes because of some special factors in disaster. Firstly, traffic capacity can be ignored because the traffic network would be controlled by transportation department. Secondly, the buffer time is difficult to estimate because traffic conditions are unknown after disaster, thus the traffic accessibility is used to build the new index for disaster recovery. Thirdly, distance of damaged roads is an important factor. The parameters of disaster scale or damage level are also discussed. However, the simulated results from this model are imperfect because some disaster areas are unpredictable and only the historical data can be use. Therefore, more factors and simulations should be considered to improve this model in the future.


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