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ROUNDABOUT PLANNING AND DESIGN FOR EFFICIENCY & SAFETY CASE STUDY: WILSON STREET/MEADOWBROOK DRIVE/ HAMILTON DRIVE CITY OF HAMILTON

Roundabouts are becoming more widely recognized for their capacity and safety advantages over traffic signals for moderate to high traffic flows. Accordingly, the city of Hamilton considered the feasibility of establishing a roundabout at the intersection of Wilson Street, Meadowbrook Drive and Hamilton Drive in the Town of Ancaster. Wilson Street, a former Provincial secondary highway, connects the village of Ancaster to the City of Brantford. SRM Associates, also branded as Roundabouts Canada, performed a preliminary analysis of the potential operational performance of a modern roundabout for this intersection. The evaluation criteria determining whether a roundabout is feasible at any one intersection required the comparison of traffic capacity performance between a roundabout and a traffic signal and cost benefit comparison of a signalised intersection versus a roundabout including lifecycle cost analysis. The preliminary geometric parameters and the safety performance prediction for a roundabout were developed using RODEL, a capacity and safety prediction model, based on extensive research of existing roundabouts, that relates geometry to capacity and safety performance. Through this investigation it was determined that the subject intersection could benefit from implementation of a roundabout in terms of traffic capacity and operational performance. The predicted performance of this intersection as a roundabout is documented with a high degree of confidence that the forecast 20 to 25 year traffic flows will not generate excessive queuing or delay when compared to traffic signal control. An initial study into the feasibility of a roundabout at this intersection included public consultation to establish a roundabout as the preferred intersection control in consideration of alternatives such as traffic signals, all-way stop control and two-way stop control. The study prudently recommended a single lane roundabout with single lane entries and exits, acknowledging the scarcity of roundabouts on arterial roads in Southern Ontario and the need for predictable, uncomplicated operation. This design brief accurately demonstrates that a roundabout will provide a safe form of intersection control to service traffic forecasts for beyond the useable life of the proposed operational improvements. The design of the proposed roundabout at the intersection of Wilson Street, Meadowbrook Drive and Hamilton Drive in the City of Hamilton has been prepared using state of the art empirically based methods for predicting capacity, delay and queuing with a high degree of confidence. The proposed design suits local conditions, being capable of accommodating twice the existing traffic volume without undue vehicle queuing or delay. Field studies of before and after spot speeds indicate that the design operating speed of 30 to 40 km/h for traffic through the roundabout has been achieved owing to specific consideration for entry deflection and fastest path of a passenger car. Over the sixth months following the opening of the roundabout, one single motor vehicle crash without injury was reported.

Author

Lenters, M

Session title

INNOVATIONS IN TRAFFIC OPERATIONS SAFETY

Organizers

Traffic Operations & Management Standing Committee

Year

2003

Format

Paper

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