Evaluation of displaced left-turn intersections

Abdelrahman, Ahmed; Abdel-Aty, Mohamed; Lee, Jae Young; Yue, Lishengsa; Al-Omari, Ma’en Mohammad Ali

doi:10.1016/j.treng.2020.100006

Cited by 11 publications

(6 citation statements)

References 8 publications

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“…The safety performance of UAIDs can be assessed using different measures, such as theoretical number of conflict points, real-life crash data, and traffic microsimulation analysis using surrogate safety measures. Several studies have investigated the safety performance of different UAIDs designs using crash data and simulation models including the SSM design ( 20–25 ), the DLT ( 6, 26–28 ), the continuous green T-intersection (CGT) ( 29, 30 ), and the jughandle intersection ( 31 ). Najaf and Pulugurtha ( 32 ) compared the safety performance of six UAIDs (unsignalized MUT, signalized MUT, the SSM, bowtie, forward jughandle, and reverse jughandle) relative to three conventional intersection designs.…”

Section: Previous Workmentioning

confidence: 99%

Operational and Safety Performance Evaluation of Parallel Flow Intersection

Abobakr

Esawey

Osama

2022

Transportation Research Record

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Unconventional arterial intersection designs have recently gained popularity as an alternative solution to alleviate congestion and mitigate safety problems of at-grade signalized intersections. This study investigates the operational and safety performance of the parallel flow intersection (PFI) under different balanced and unbalanced traffic volume conditions in comparison with a conventional counterpart using VISSIM microsimulation and Surrogate Safety Assessment Model software. The operational performance of the two intersections was based on the overall intersection capacity and the average vehicle delay. The safety performance, on the other hand, was based on the number and severity of simulated conflicts. The results showed that the PFI had a higher capacity compared with the conventional intersection under balanced volume conditions. Under unbalanced volume levels, the PFI outperformed the conventional intersection especially with an increase of left-turn volumes. Moreover, the PFI enhanced the safety conditions relative to the conventional intersection by eliminating all the crossing conflicts under all balanced and unbalanced volume levels and reducing the total number and severity of conflicts at all volume conditions. The study provides guidelines for the optimal spacing distance between the main and secondary intersections for the implementation of the PFI based on its safety and operational impacts on the intersection.

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Section: Previous Workmentioning

confidence: 99%

Operational and Safety Performance Evaluation of Parallel Flow Intersection

Abobakr

Esawey

Osama

2022

Transportation Research Record

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“…Yang et al verified with simulation that a proposed signal optimization model can provide enough green time to through and heavy turning movements while preventing queues from spilling over on the left-turning bays [10]. Alternatively, few studies have used infrastructure-based Automated Traffic Signal Performance Measures (ATSPMs) [4] [12] to assess performance at CFIs [13].…”

Section: Most Of the Cfi Performance Studies Have Been Based On Micro...mentioning

confidence: 99%

Continuous Flow Intersection Performance Measures Using Connected Vehicle Data

Saldivar-Carranza¹,

Li²,

Taylor³

et al. 2022

JTTs

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Continuous flow intersections (CFIs), also known as displaced left turns (DLTs), are a type of alternative intersection designed to improve operations at locations with heavy left-turn movements by reallocating these vehicles to the left side of opposing traffic. Currently, simulation is commonly used to evaluate operational performance of CFIs. However, this approach requires significant on-site data collection and is highly dependent on the analyst's ability to correctly model the intersection and driver behavior. Recently, connected vehicle (CV) trajectory data has become widely available and presents opportunities for the direct measurement of traffic signal performance measures. This study utilizes CV trajectory data to analyze the performance of a CFI located in West Valley City, UT. Over 4500 trajectories and 105,000 GPS points are analyzed from August 2021 weekday data. Trajectories are linear-referenced to generate Purdue Probe Diagrams (PPDs) and extended PPDs to estimate split failures (SF), arrivals on green (AOG), traditional Highway Capacity Manual (HCM) level of service (LOS), and the distribution of stops. The estimated operational performance showed effective progression during the PM peak period at all the critical internal storage areas with AOG levels at exit traffic signals between 83% and 100%. In contrast, all external approaches with longer queue storage areas had AOG values ranging from 2% to 81% during the same time period. The presented analytical techniques and summary graphics provide practitioners with tools to evaluate the performance of any CFI where CV trajectories are available without the need for on-site data collection.

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“…In addition, the authors also found that some other factors have significant effects on the crash frequency. For example, they found that crash frequency decreases when the minor street has a low-speed limit [18].…”

Section: Literature Reviewmentioning

confidence: 99%

Statistical Analysis of Safety Performance of Displaced Left-Turn Intersections: Case Studies in San Marcos, Texas

Sun

Zhao

et al. 2020

IJERPH

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Displaced left-turn (DLT) intersections are designed to increase the mobility of vehicles by relocating the left-turn lane (lanes) to the far-left side of the road upstream of the main signalized intersection. Since DLT is a relatively new design and very limited crash data are available, previous studies have focused mainly on the analysis of its operational performance rather than its safety performance. To fill this gap, in this study, we investigated the safety performance of two DLT intersections located in San Marcos, Texas. Crash data from 2011 to April 2018 were extracted from the TxDOT Crash Record Information System (CRIS). These crash data were analyzed using two different approaches, i.e., statistical analysis and collision diagram-based analysis. The results of this study indicated that DLT did not increase the overall crash frequencies at the studied intersections. Traffic crashes related to left turns and right turns were reduced significantly by DLT. Meanwhile, it also caused safety issues related to traffic signage, traffic signal, geometric design, and access management at DLT intersections. Thus, in the implementation of DLT intersections, traffic engineers need to carefully consider different aspects of the DLT intersection design, including access management, traffic signal coordination, and driver acceptance. As a result of these analyses, recommendations were provided for the safe implementation of the DLT design in the future.

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Evaluation of displaced left-turn intersections

Cited by 11 publications

References 8 publications

Operational and Safety Performance Evaluation of Parallel Flow Intersection

Operational and Safety Performance Evaluation of Parallel Flow Intersection

Continuous Flow Intersection Performance Measures Using Connected Vehicle Data

Statistical Analysis of Safety Performance of Displaced Left-Turn Intersections: Case Studies in San Marcos, Texas

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