A comparative analysis of the performance of turbo roundabouts based on geometric characteristics and traffic scenarios

Dabiri, Amir Reza; Aghayan, Iman; Hadadi, Farhad

doi:10.1080/19427867.2020.1757198

Cited by 5 publications

(6 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many studies regarding trafc in at-grade signalized intersections used Synchro [35][36][37][38][39][40]. By considering diferent HCM criteria [41,42], Synchro was selected because it contains the sixth edition of HCM (HCM2016). Te average control delay (d) for each lane is based on the following formula:…”

Section: Methodsmentioning

confidence: 99%

The Effect of the Number of Right-Turn and Left-Turn Lanes on the Performance of Undersaturated Signalized Intersections

Rahmani

Nasiri

Aghayan

2023

Journal of Advanced Transportation

Self Cite

View full text Add to dashboard Cite

Vehicle traffic flow channelizing can significantly contribute to fewer collisions and smooth traffic flow in isolated signalized intersection design. Therefore, this study investigates the effect of changes in the number of right-turn lanes with splitter islands and left-turn storage bays for different volume approaches on intersection performance. This study aims to provide an accurate analysis to estimate the effect of such changes on signalized intersections, which can improve intersection performance. Furthermore, the delay parameter derived from HCM2016 and simulation was evaluated for different scenarios. For this purpose, simulation was performed using Synchro software. In this study, a symmetrical, 90-degree, undersaturated (volume per capacity lower than 1, V/C < 1), and four-leg intersection were considered according to AASHTO Green Book 2018 suggestions. HCM2016 results indicated the delay parameter was less sensitive to the undersaturated condition than the right-turn volume variation for both single and dual-lane bays. However, the simulation results indicated that the delay parameter was not constant, depending on the number of right-turn lanes and volumes. On the other hand, there was a significant difference in delay parameters between the single and dual left-turn lanes for both simulation and HCM cases estimated 77.4% and 59.7%, respectively. Overall, this study can provide a vision for traffic engineers to modify the geometry of the four-leg signalized intersections, if the right-turn or left-turn demand volume of an undersaturated signalized intersection is larger than the through approach.

show abstract

Section: Methodsmentioning

confidence: 99%

The Effect of the Number of Right-Turn and Left-Turn Lanes on the Performance of Undersaturated Signalized Intersections

Rahmani

Nasiri

Aghayan

2023

Journal of Advanced Transportation

Self Cite

View full text Add to dashboard Cite

show abstract

“…On the contrary, a multi-lane roundabout has a better traffic capacity, but may lack in traffic safety. Based on this contradiction, a turbo roundabout is a relatively new type, which provides a spiraling flow of traffic that forces drivers to choose their direction before entering the roundabout, thereby enhancing the levels of both safety and capacity [23,24].…”

Section: Types Of Roundaboutsmentioning

confidence: 99%

An Overview of the Efficiency of Roundabouts: Design Aspects and Contribution toward Safer Vehicle Movement

Gkyrtis,

Kokkalis

2024

Vehicles

View full text Add to dashboard Cite

Transforming intersections into roundabouts has shown that a sufficient degree of road safety and traffic capacity can be achieved. Because of the lower speeds at the area of a roundabout, drivers tend to become more easily adaptive to any kind of conflict with the surrounding environment. Despite the contribution to safety, the design elements of roundabouts are not uniformly fixed on a worldwide scale because of different traffic volumes, vehicle dimensions, drivers’ attitude, etc. The present study provides a brief overview of the contribution of roundabouts to road safety and the interactions between safety and the design elements of roundabouts. In addition, discussion points about current challenges and prospects are elaborated, including findings from the environmental assessment of roundabouts; their use and performance on the era of autonomous vehicles that will dominate in the near future; as well as the role and importance of simulation studies towards the improvement of the design and operation of roundabouts in favor of safer vehicle movement. The criticality of roundabouts, in terms of their geometric design as well as the provided road safety, lies upon the fact that roundabouts are currently used for the conventional vehicle fleet, which will be gradually replaced by new vehicle technologies. Such an action will directly impact the criteria for road network design and/or redesign, thereby continuously fostering new research initiatives.

show abstract

“…If turbo roundabout is compared with elliptic and modern intersections with or without signalisation, it is observed that the increase has a positive effect on delay time and capacity in all signalised intersections under all flow conditions. Chenwei and Xiaodan (2017) Izadi et al (2016); Dabiri et al (2020) assert that when conventional and turbo roundabouts are compared to conventional roundabouts in different scenarios with respect to performance of delay time, capacity and level of service, in case that the diameter of the four-leg turbo roundabout is increased, the performance of the conventional roundabout decreases but the performance of the three-leg turbo roundabout increases. Liu et al, (2020) conclude that when turbo roundabouts with different central island diameters are designed, the performance of the roundabout can change according to the number of legs.…”

Section: Alternative Roundabout Types and Their Comparisonmentioning

confidence: 99%

Performance Evaluation of a Hybrid Roundabout Using a Microscopic Simulation

User

İlyas²,

Tınaztepe

2021

BJRBE

View full text Add to dashboard Cite

Roundabouts are one of the safest types of intersections. There are a number of roundabout types in literature. Each roundabout type is distinguished by some characteristics. To design more efficient junctions, hybrid roundabouts can be created by combining their required characteristics geometrically. In this study, the safety feature of the turbo junction type and the easing up the traffic density feature of the hamburger junction have been combined. Some geometric parameters and layout details of the proposed hybrid roundabout are given, and its performance was simulated in a signalised 4-leg roundabout as the most frequently used intersection in Antalya. The performance of the proposed hybrid roundabout was compared with the status in 2016 and the current status in 2017 and beyond of the roundabout through AIMSUN transport simulation software. In regard to performance analysis, delay time, travel time, speed, density, fuel consumption, number of stops, queuing, carbon emission were analysed for all statuses and compared. In addition, traffic safety analysis has been performed for all statuses and compared. Results show that the overall average performance of the proposed roundabout increases by 40% and 41.8% in comparison with the statutes in 2016, 2017 and beyond, respectively. The proposed roundabout is 41% safer than the status in 2016, and the accident risk is lower by 18.5% than the current status.

show abstract

A comparative analysis of the performance of turbo roundabouts based on geometric characteristics and traffic scenarios

Cited by 5 publications

References 23 publications

The Effect of the Number of Right-Turn and Left-Turn Lanes on the Performance of Undersaturated Signalized Intersections

The Effect of the Number of Right-Turn and Left-Turn Lanes on the Performance of Undersaturated Signalized Intersections

An Overview of the Efficiency of Roundabouts: Design Aspects and Contribution toward Safer Vehicle Movement

Performance Evaluation of a Hybrid Roundabout Using a Microscopic Simulation

Contact Info

Product

Resources

About