01367713

Component

With the increased prevalence of roundabouts in the United States, there is a need to evaluate the performance of roundabouts relative to other intersection control strategies. Unfortunately, few studies have compared roundabouts with other intersection control strategies in a systematic fashion. Consequently, this paper compares four types of intersection control strategies considering a single lane approach with a 35 mi/h (58 km/h) speed limit considering equal demand on all approaches. The study demonstrates that vehicle delay is minimized with the use of a roundabout intersection control for all demand levels below 500 veh/h/approach. Above this point if the left turn percentage exceeds 70%, traffic signal control is more efficient. The roundabout alternative also produces the fewest vehicle stops for low demand levels, low left turn demand and high right turn demand, however a TWSC alternative produces the least number of vehicle stops when the through and total demand is high. The study demonstrates that for low traffic demand levels roundabouts should be considered in the design alternatives for isolated intersection control. The paper also shows that for over-saturated conditions a traffic signal does not necessarily produce the least delay when using the Webster-Cobb method; instead the shortest cycle length with the simplest phasing scheme may result in less vehicle delay and stops.

This paper was sponsored by TRB committee ANB75T Roundabouts

01362476

12-0804

English

19p

2012

Transportation Research Board 91st Annual Meeting

Digital/other

Figures; References

Demand; Highway design; Intersections; Roundabouts; Traffic delays; Traffic oversaturation; Traffic simulation

Highways; Operations and Traffic Management; I73: Traffic Control

Transportation Research Board Annual Meeting 2012 Paper #12-0804

TRIS, TRB

Feb 8 2012 4:57PM