The Geometric Design Standards and the Enhanced Clear Zone Concept as Utilized on the Trans Canada Highway Project

The selection of geometric design standards which should be utilized for a Private / Public Partnership (P3) project is a question that must always be considered by the facility’s owner especially in the current era of design domains. The paper shows how the standards were developed for the 98 kilometre Trans Canada Highway project in New Brunswick. A brief description of the Trans Canada Highway Project (TCHP) and how it fits into the overall transportation system in the province is provided. The paper describes how each geometric design feature was evaluated based on the owner’s engineer having a thorough knowledge of the project to be constructed and the adjacent network in which the project was to be incorporated. It is recognised that the project standards must be consistent with this adjacent network. It also talks about how many features of this project, such as the horizontal alignment standards for the main lanes, are essentially pre-determined by the owner. This determination is the result of the owner having to select standards for preconstruction activities such as the establishment of the Right of Way (ROW). The paper also discusses how the change request process allows both the Developer and the Owner to deal with specific instances where it might be advantageous for both parties to vary from the project’s standards. It also talks about the lessons learned from the project in relation to the establishment of geometric design standards. The paper also talks about the application of an enhanced clear zone concept and how it was used on the project. This concept allowed for low cost safety improvements to be undertaken outside the traditional clear zone limits in order to add value to the project. These enhanced clear zone improvements were utilized both for the new construction and the upgrading of the adjacent existing sections. The paper concludes that by having the owner’s engineer having a thorough knowledge of both the P3 project and the adjacent network a set of geometric project standards can be developed that allow the project to be consistent with the adjacent system, without completely limiting the Developer’s flexibility. It also concludes that the enhanced clear zone concept can cost-effectively add safety improvements to both the areas of new construction and on the adjacent highway system.