An innovative design for left turn bicycles at continuous flow intersections

Zhao, Jing; Gao, Xing; Knoop, Victor L.

doi:10.1080/21680566.2019.1614496

Cited by 9 publications

(7 citation statements)

References 53 publications

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“…In addition, relevant papers have also studied the design scheme of pedestrian crossing facilities at CFIs [39]. The innovative design of a left-turn bicycle at a CFI has been put forward, which can eliminate the conflict between left-turn bicycles and opposite through vehicles [3]. In addition, a geometric improvement to the CFI was analyzed to enhance pedestrian accommodations [41].…”

Section: Geometric Layout Of Cfimentioning

confidence: 99%

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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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Section: Geometric Layout Of Cfimentioning

confidence: 99%

“…An intersection is a bottleneck node in an urban road network [3]. Solving the congestion of intersections is the key to settling down the problem of urban traffic congestion, while the conflict between left-turn and through vehicles is the key factor in increasing vehicles' delay and reducing vehicle throughput of intersections [4][5][6].…”

Section: Introductionmentioning

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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“…The start of green of the through movement from a leg equals the end of the left-turn phase from the opposing leg, as shown in Eqs. (8) and (9). The start of green of the left-turn from east and west legs should be the same, which equals the end of through phase from the north and south legs, as shown in Eqs.…”

Section: B Constraints 1) Calculation Of the Vehicular Delaymentioning

confidence: 99%

Robust Signal Control of Exit Lanes for Left-Turn Intersections With the Consideration of Traffic Fluctuation

et al. 2020

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Traffic throughput at intersections can be improved by using exit lanes for left-turning (EFL), tidal flow lanes near an intersection, which has been recently introduced. This paper considers the operational robustness of the EFL intersection in relation to the control scheme applied to the traffic light setting. For safety and efficiency, it is important that the tidal lanes are emptied before traffic in the opposing direction uses these lanes. Hence, the signal control should not only be optimized for the mean value but be robust for all kinds of fluctuations. This paper formulates a traffic control scheme using robust optimization, i.e. an optimization scheme which explicitly accounts for extreme events. The fluctuation of traffic is considered from three aspects: the distribution of traffic demand, the distribution of base saturation flow rate, and the distribution of actual travel speed. Via a case study and extensive numerical analysis, we find that the established robust optimization method produces an efficient design of signal control and design speed at the EFL intersection under traffic demand and supply fluctuations. Though the optimization method is now applied to intersections with an EFL, it is considered useful for all intersections with high fluctuation of traffic demand and saturation flow rate. INDEX TERMS Exit-lanes for left-turn intersection, robust optimization, signal control, unconventional intersections.

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“…Besides, researchers have developed a left-hand excursion plane crossing design process [29]. Because of the increasing popularization of low-carbon travel in China, researchers have proposed a displaced left-turning bicycle lane based on the concept of a DLT lane [30]. Some scholars have put forward a new simplified DLT intersection (called CFI-Lite) on the basis of a DLT intersection and have verified its practicability [31].…”

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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An innovative design for left turn bicycles at continuous flow intersections

Cited by 9 publications

References 53 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

Robust Signal Control of Exit Lanes for Left-Turn Intersections With the Consideration of Traffic Fluctuation

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

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