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Design and Implementation of Slot Left-Turn Lanes on the Manitoba Highway Network


Provincial Trunk Highway (PTH) 12 in the City of Steinbach, Manitoba, is a 4-lane divided roadway. As it was originally designed to expressway standards, the medians are wide to provide appropriate separation of traffic. Making direct left turns from PTH 12 is problematic because the large intersection footprint results in poor sightlines when signalized and adds to driver confusion, with many drivers making left turns by passing opposing left-turn traffic on the right. The City of Steinbach has seen rapid growth over the past decade, and development along PTH 12 has necessitated the improvement of operations at several intersections. Manitoba Infrastructure and Transportation (MIT) has begun implementing slot left-turn lanes in an attempt to remediate these issues. Three intersections in Steinbach have received this treatment over the past seven years and public reaction appears to be positive. Proper selection of design speed and vehicle are crucial when designing slot left-turn lanes. Furthermore, signage and lane markings must be appropriate for both seasoned urban drivers and rural drivers who are unfamiliar with this form of channelization. The configuration and location of a raised divisional island must take into account maintenance (snow clearing) and emergency vehicle access. MIT has used the knowledge gained in designing, constructing and operating slot left-turns to refine the design for future applications.

Conference Paper Details

Session title:
Brent Hartmann
Derek Durant
Geometric design