Deerfoot Trail Extension – Innovative Approach Leads to Geometric Innovations

The Deerfoot Trail Extension is 11 km of new freeway, which was completed in 2004. The project cost $100M, and extends south from Hwy 22X to the existing Hwy 2 / 2A interchange south of Calgary. This completes a previously missing direct link in Hwy 2, which is part of the North / South trade corridor through Alberta. In 1998, Alberta Infrastructure and Transportation (AIT) developed an innovative RFP that: • Combined what previously would have been four large projects into one very large project. • Encouraged consultants to propose innovative approaches. In response, the “Partners in Excellence” Team was formed, including UMA Engineering Ltd., AMEC Infrastructure Ltd., AMEC Earth & Environmental Ltd., and Associated Engineering (Alberta) Ltd. The team developed an innovative approach, incorporating a “Board of Control”, “Partnering” and “Value Engineering” to foster collaboration and drive innovation through all project phases. This approach resulted in: • two geometric innovations that saved $8M while improving safety. • environmental innovations that exceeded requirements, at no additional cost. • a project which has been receiving accolades since opening. This paper will provide an overview of the project, the process that led to innovation, and the two major geometric innovations, the “two lane loop ramp”, and the “major fork”. The existing “Okotoks Interchange” connects Highways 2, 2A, and 552 at the south end of the project. Previous functional planning found that the existing single lane loop ramp, which carries eastbound to northbound traffic, was nearing capacity, and proposed a short term conversion to a diamond interchange style dual left turn, and ultimately a directional ramp. Our team proposed a two lane loop ramp, which would significantly defer the requirement for the costly directional ramp, while removing the safety concerns with the dual left turn across opposing traffic. About 1 km north of the Okotoks interchange, Hwy 2 splits into MacLeod Trail and Deerfoot Trail, in a “Y” configuration. Conventional design has the “minor” roadway exiting on the right, even though the roadway eventually goes to the left. The resulting grade separation structure would have a minimum radius, with maximum superelevation, leading to potential bridge icing related safety concerns. In this case, although Deerfoot Trail is the “new” Hwy 2, functional planning indicated both roadways would have similar volumes.