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

Qu, Wenrui; Sun, Qiao; Zhao, Qun; Tao, Tao; Qi, Yi

doi:10.3390/ijerph17186446

Cited by 5 publications

(3 citation statements)

References 8 publications

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“…In terms of capacity, a full CFI is better than a partial CFI [35]. In addition, signing and marking, as well as traffic safety benefits of the CFI, have also been of interest [49,50].…”

Section: Traffic Efficiency Of Cfimentioning

confidence: 99%

Evaluation and Analysis of CFI Schemes with Different Length of Displaced Left-Turn Lanes with Entropy Method

et al. 2021

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As an unconventional design to alleviate the conflict between left-turn and through vehicles, Continuous Flow Intersection (CFI) has obvious advantages in improving the sustainability of roadway. So far, the design manuals and guidelines for CFI are not enough sufficient, especially for the displaced left-turn lane length of CFI. And the results of existing research studies are not operational, making it difficult to put CFI into application. To address this issue, this paper presents a methodological procedure for determination and evaluation of displaced left-turn lane length based on the entropy method considering multiple performance measures for sustainable transportation, including traffic efficiency index, environment effect index and fuel consumption. VISSIM and the surrogate safety assessment model (SSAM) were used to simulate the operational and safety performance of CFI. The multi-attribute decision-making method (MADM) based on an entropy method was adopted to determine the suitability of the CFI schemes under different traffic demand patterns. Finally, the procedure was applied to a typical congested intersection of the arterial road with heavy traffic volume and high left-turn ratio in Xi’an, China, the results showed the methodological procedure is reasonable and practical. According to the results, for the studied intersection, when the Volume-to-Capacity ratio (V/C) in the westbound and eastbound lanes is less than 0.5, the length of the displaced left-turn lanes can be selected in the range of 80 to 170 m. Otherwise, other solutions should be considered to improve the traffic efficiency. The simulation results of the case showed CFI can significantly improve the traffic efficiency. In the best case, compared with the conventional intersection, the number of vehicles increases by 13%, delay, travel time, number of stops, CO emission, and fuel consumption decrease by 41%, 29%, 25%, 17%, and 17%, respectively.

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“…In terms of capacity, a full CFI is better than a partial CFI [35]. In addition, signing and marking, as well as traffic safety benefits of the CFI, have also been of interest [49,50].…”

Section: Traffic Efficiency Of Cfimentioning

confidence: 99%

Evaluation and Analysis of CFI Schemes with Different Length of Displaced Left-Turn Lanes with Entropy Method

et al. 2021

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“…Otkovic et al [9] used the neural network to calibrate the VISSIM simulation model and applied the model on selected case study and gave basic insight to the methods of calibration of VISSIM microsimulation traffic for urban transport network. Otherwise, Qu et al [10] stated that DLT did not increase the crash rate of overall studied intersections and crash rates that are related to left and right turn were reduced significantly.…”

mentioning

confidence: 88%

Traffic simulation of continuous flow intersection with displaced left-turn: a case study

Alkaissi

2022

J. Eng. Appl. Sci.

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Today, our community is facing a growing numbers of transportation challenges, as traffic grows and congestion worsens for signalized intersections. Based on that its needed balances solutions that improve safety and keep mobility for users with minimum travel time. The objective of this research is to investigate the implementation of continuous flow intersection with displaced left turn with developed simulation traffic model by VISSIM program to evaluate the traffic operation impacts of displaced left turn on performance of signalized intersection in terms of vehicle delay, length of queue, and stopped delay. This research studied congested signalized intersections in Baghdad City. An innovative solution of continuous flow intersection with displaced left turn was implemented to alleviate congestion and high vehicle delay.The displaced left turn DLT reduced the average vehicle delay about 44% and improved the deterioration level of service from (F) to better level of service (D) for north and south approaches which represented the most congested legs of intersection during the peak period. The results of stopped delay for DLT intersection with developed signal timing were lowest than the conventional intersection by about 51% and 34% for south and north approaches respectively. This implies that DLT intersection reduced the extra stops of vehicle and improved the overall efficiency of signalized intersection. The reduction in the queue length ranged from 47.5 to 42%; otherwise conventional intersection showed long queue length and higher vehicle delay. Therefore, regarding queue length, DLT intersection with developed signal timings strategy had better performance for traffic operation than conventional intersection.

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“…To date, some scholars have carried out meaningful studies on DLT intersections, such as the applicability of displaced left-turn intersections, and have put forward two forms: partial and complete DLT intersections [7]. rough observation data of actual DLT intersections, the advantages of DLT intersections with improving traffic safety in turning can be found [24]. In addition, other scholars have also studied the safety of DLT intersections by using before-and-after comparison group and cross-sectional analysis methods and then pointed out that DLT intersections need to be equipped with traffic signs and traffic-calming facilities to achieve better use results [25].…”

Section: Introductionmentioning

confidence: 99%

Evaluation and Analysis Model of the Length of Added Displaced Left-Turn Lane Based on Entropy Evaluation Method

Pan

Ying

Luo

et al. 2021

Journal of Advanced Transportation

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As the number of vehicles continues to grow in China, the problem of urban traffic congestion gets more serious, particularly at intersections. As a new type of unconventional intersection, the displaced left-turn (DLT) intersection has been widely recognized to improve the efficiency of intersections with heavy left-turn traffic flows. Converting an existing intersection into an intersection with additional DLT lanes is a valuable solution. However, the studies on DLT intersections mainly focus on performance, applicability, and safety. The guidelines on the specific engineering design process mostly come from experience, and the study on the considering multifactor design method is still insufficient. Therefore, this paper proposed an evaluation and analysis model of the lengths of added DLT lanes based on the entropy evaluation method, in which VISSIM and Surrogate Safety Assessment Model (SSAM) software were adopted for simulation. A design process for the length of the added DLT lanes was proposed with this model. An urban intersection in Xi’an was taken as a case study, and the application of the model and the design process was studied in detail. After selecting four evaluation indicators, the model was applied to calculate and analyze the optimal length of the added DLT lanes under 45 different traffic volume combinations. The recommended lengths of different situations were within the range recommended in the guidebook published by Federal Highway Administration. The results of the case study proved that the model proposed in this paper was advanced, reasonable, and practical.

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

Cited by 5 publications

References 8 publications

Evaluation and Analysis of CFI Schemes with Different Length of Displaced Left-Turn Lanes with Entropy Method

Evaluation and Analysis of CFI Schemes with Different Length of Displaced Left-Turn Lanes with Entropy Method

Traffic simulation of continuous flow intersection with displaced left-turn: a case study

Evaluation and Analysis Model of the Length of Added Displaced Left-Turn Lane Based on Entropy Evaluation Method

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