Open Collections

Juniper, Scott Heath

University of British Columbia

As relatively novel intersections, roundabouts have garnered support and interest from many countries due to traffic flow and safety improvements over traditional intersections. Despite growing application, knowledge and experience is relatively scarce within Canada for multilane roundabouts (MLR’s); the Canadian Roundabout Design Guide was only published in 2017 and was largely based on US guidance. Turbo Roundabouts are an emerging multi lane roundabout design successfully implemented in Europe over the past 20 years, however nowhere yet applied in Canada, and rarely in the United States. Claimed to reduce safety risk for all users (not just automobile), decrease greenhouse gas emissions, increase climate resiliency, and reduce lifecycle costs for an intersection, Turbo Roundabouts present a MLR design option that warrants consideration for Canada; there is also considerable opportunity to implement this design due to increased capacity over a single lane roundabout. Many research teams have demonstrated injury risk being significantly lower to auto and non-auto road users by implementing this design. This lower risk is due to several design features, including spiral circulating lanes, physical lane dividers, and adequate separation for pedestrian and bicyclist crossings – among others. This research determined Turbo Roundabouts are applicable to Canada, have significant potential social, environmental, travel time, and safety benefits, however knowledge gaps exist to accommodate design. Research methods included literature review of existing MLR design, a case study feasibility design project, and field visits to existing Turbo Roundabouts in Europe. Findings of the research were that Turbo Roundabouts cannot be applied in Canada without a few adjustments; particularly, lane divider width, circulating radii, and entry radii would need modification for the longer design vehicles in Canada. Snow removal equipment was not found to be a barrier to Turbo Roundabout implementation, contrary to common perception. An innovative intersection like Turbo Roundabouts would likely require driver education as well. Existing Canadian design guidelines have yet to provide guidance for Turbo roundabouts, and no planning level tools exist pertaining to Canadian specific requirements. There are currently two roundabouts constructed in Canada that aspire to some aspects of turbo roundabout design features, despite hundreds constructed in Europe.

Text

2024-08-01

Attribution-NonCommercial-ShareAlike 4.0 International

http://hdl.handle.net/2429/88839

Civil Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-sa/4.0/