Impact of U-Turns as Alternatives to Direct Left-Turns on the Operation of Signalized Intersections

Taha, Mahmoud A.; Abdelfatah, Akmal

doi:10.12720/jtle.3.1.12-17

Cited by 7 publications

(9 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…16 (Taha and Abdelfatah, 2015) SYNCHRO and VISSIM -Typical 4-leg Intersection -Under most traffic conditions, the results of the analysis showed that unconventional left-turn control forms could have greater operational performance than direct left-turns. 17 (Msallam et al, 2016) HCS2000 and SYNCHRO-8 Jordan Eight signalized intersections…”

Section: Selected Intersections Manuallymentioning

confidence: 99%

“…The third and fourth alternatives were shown to be important in increasing service quality, although the third alternative was more cost-effective. Taha and Abdelfatah (2015) reported that in comparison to the straight left-turn, the unconventional left-turn control type has less delay. In addition, among all left-turn control types, the U-turn followed by the right-turn (UTRT) control type has the shortest travel time.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Traffic Assessment And Optimization at Signalized Intersections: A Review Study

Hasan

Hussein²

2022

UOD

View full text Add to dashboard Cite

Signalized intersections are critical elements of the highway system, thus improving the attitude of these intersections significantly influences the overall operating performance of the highways in respect of delay and level of service (LOS). Reduction in capacity and increase in delay at signalized intersections could be a reflection of poor signal timing as well as inadequate road geometry variables. A better comprehension of the reasons that affect signalized intersections performance can be useful in reducing delay and improving the LOS. This study aims toreview some of thepublished works on the evaluation of traffic operation at signalized intersections using both Highway Capacity Manual 2010 (HCM 2010) and several optimization software. Different approaches were used to identify the main input data (traffic volume data, geometric characteristics, and signal timing) required for the HCM and different optimization proposals including video recording technique and field survey. The outcomes of thepublished investigations indicated to improve the operational performance of these intersections including cycle length, adding lanes, creating overpass, prohibiting approach traffic from the intersection, and a combination of some proposals.The research also seeks to add tothis review the limitations of using different software suchas SYNCHRO, CORSIM, HCS, SIDRAand the considerable variability of delays and LOS using these software’s so that it may be updated for future experimental and simulation investigations on signalized intersections

show abstract

Section: Selected Intersections Manuallymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Traffic Assessment And Optimization at Signalized Intersections: A Review Study

Hasan

Hussein²

2022

UOD

View full text Add to dashboard Cite

show abstract

“…They concluded that, roundabouts performed better than stopcontrolled intersections. (Taha and Abdelfatah, 2015) used VISSIM software to evaluate the operational effects of three left-turn control types including direct left-turn, right-turn followed by U-turn, and U-turn followed by right-turn. The results of this study proved that, unconventional left-turn control types could have better operational performance than direct leftturns, under most of traffic conditions.…”

Section: Previous Studiesmentioning

confidence: 99%

Evaluation of Operational and Environmental Performance of Median U-Turn Design Using Micro-Simulation

Hashim¹,

Ragab²,

Asar³

2017

IJTTE

View full text Add to dashboard Cite

Road intersections force vehicles to slow down and stop in varying patterns and contribute to the increase in vehicular emissions. The main aim of this paper is to evaluate the operational and environmental performance of median U-turn design. Also, it aims to compare this design with conventional three-leg and signalized three-leg intersections in terms of average delay, fuel consumption and air emissions including carbon monoxide (CO), nitrogen oxides (NO X ) and hydrocarbons (HC). The microscopic traffic simulation model VISSIM was used to model and analyze the three designs under a wide range of balanced and unbalanced flow conditions. The results indicated that, the median U-turn (MUT) design exhibited slightly lower delays than conventional three-leg intersection at balanced volume scenarios, up to approximately 1250 veh/hr/approach. After this volume level, the median U-turn (MUT) design exhibited higher delays than three-leg intersection. Also, the median U-turn (MUT) design exhibited lower air emissions and fuel consumption than other intersections at all balanced volume scenarios. In addition, under unbalanced volume scenarios, the average delay, air emissions and fuel consumption increased with the increase of main and/or cross street volumes for the median U-turn (MUT) design.

show abstract

“…Evaluation of the expected operational benefits of the SM intersection design has been conducted in this study in the microscopic simulation environment. PTV Vissim software is commonly used for the microscopic simulation of unconventional intersections ( 14–18 ), while Synchro software is mainly used for signal timing optimization ( 5 , 19 ). Therefore, PTV Vissim software has been employed to simulate RCUT and SM intersection designs along with the conventional four-leg intersection, while Synchro software has been used for the optimization of signal timing.…”

mentioning

confidence: 99%

Evaluation of a New Intersection Design, “Shifting Movements”

Al-Omari

Abdel-Aty

2021

Transportation Research Record

View full text Add to dashboard Cite

Several unconventional designs have been suggested to enhance traffic operation and safety at intersections. However, the operational benefits of implementing some of them are achieved only under certain traffic conditions. For instance, the operational performance of the restricted crossing U-turn (RCUT) intersection design manifests only under highly unbalanced traffic conditions. The RCUT intersection outperforms conventional intersections that are subjected to high major traffic and light minor traffic volumes, while its operational performance fades at intersections with moderate to heavy minor road traffic. In this technical paper, a new innovative four-leg intersection design has been proposed to replace the RCUT intersection under moderate and heavy minor road traffic volumes. The new intersection design which has been named the “Shifting Movements” (SM) intersection has a low number of conflict-points compared with conventional intersections, but similar to the RCUT intersection. Therefore, similar safety benefits are expected to be achieved by the implementation of the SM intersection. Operational evaluations and comparisons between conventional, RCUT, and SM intersections have been conducted in the microscopic simulation environment. Different traffic volume levels and left-turn proportions have been assumed to represent the peak hour with moderate to high left-turn traffic. The results indicate that the SM intersection design significantly outperforms conventional and RCUT intersections that are subjected to high traffic volumes in average control delay and throughput.

show abstract

Impact of U-Turns as Alternatives to Direct Left-Turns on the Operation of Signalized Intersections

Cited by 7 publications

References 8 publications

Traffic Assessment And Optimization at Signalized Intersections: A Review Study

Traffic Assessment And Optimization at Signalized Intersections: A Review Study

Evaluation of Operational and Environmental Performance of Median U-Turn Design Using Micro-Simulation

Evaluation of a New Intersection Design, “Shifting Movements”

Contact Info

Product

Resources

About