Abstract Manager

The Highway 16 and Dalmeny Access Road/Grid 684 intersection was a  two-way, stop controlled intersection with a history of serious and fatal collisions that persisted despite numerous attempts to improve safety using conventional safety countermeasures. It was not economically viable to build an interchange at this location. The Saskatchewan Ministry of Highways (Ministry) retained Associated Engineering (Associated) to complete an In-Service Safety Review (ISSR) and included a Restricted Crossing U-Turn (RCUT) configuration as one of the options. There are several RCUT’s in the U.S., but at the time of the study, none existed in Canada. This presentation will talk about how the project evolved from an ISSR to the implementation of the first RCUT in Saskatchewan.

The project began in 2018 with an ISSR of the existing intersection that included a multi-disciplinary workshop and field review involving local police, Ministry design and operations staff, and Associated’s team of traffic safety, geometric design, and human factors specialists. An automated conflict analysis identified several instances of critical risk for right angle collisions. The ISSR evaluated several options, and the recommended solution was an RCUT.

The design of the RCUT intersection used a unique approach. Associated prepared a preliminary design to identify key RCUT design elements. The RCUT was designed to support the over-dimensional route through the intersection. Characteristics of existing RCUT intersections in the U.S. were tabulated and compared to the characteristics of the Highway 16 and Dalmeny Access Road/Grid 684 to confirm the feasibility of the RCUT.

Associated completed a Vissim analysis to identify the optimal U-turn offset distance to minimize backtracking, while allowing sufficient distance for accelerating, merging, weaving across highway traffic, and decelerating to get to the U-turn. The Vissim analysis was also used to assess capacity and travel time savings.

An engagement process was delivered to manage potential opposition to change, build awareness, and educate the public. This included a public information session; production of a narrated and rendered instructional video simulation and an instructional brochure posted on social media.

The RCUT was constructed and opened to the public in Fall 2023 and has been functioning effectively. A post construction ISSR indicated significant safety benefits and reduced peak hour delays have been realized. Positive feedback was received from the key stakeholders that were contacted during the post construction ISSR. This new intersection configuration is already being considered as a safety countermeasure in other jurisdictions in Canada.