High Tension Cable Barrier (HTCB): The Next Generation of Highway Safety

As more jurisdictions look for innovative ways and products to enhance median and roadside safety, High Tension Cable Barrier (HTCB) stands out as the latest product that delivers on safety, cost, and maintenance.  HTCB is unique in that it can accommodate hits from either side, making it an attractive choice for transportation agencies in order to reduce cross-median collisions and collision severity.  Highway agencies and designers are tasked with the challenges of learning how to implement HTCB appropriately, both alone and in conjunction with traditional guardrail. 

This paper examines the particular case of Highway 16A in the Province of Alberta and how HTCB was implemented in a 10 km section to not only reduce collision frequencies and severity, but also how a relatively new and proprietary product was implemented.  The paper discusses how horizontal and vertical geometry, cross-section, connections to existing bridgerail, and length of need all played their respective roles in determining the length and location of HTCB. Highway 16A is a busy commuter highway, a remnant of the previous Trans-Canada Highway between Edmonton and Jasper.  It now serves the cities of Spruce Grove and Edmonton and carries over 30,000 vehicles a day. There is a very narrow depressed median with no existing barriers of any kind. 

As a result, Highway 16A experienced a large number of cross-median collisions.  Alberta Transportation (AT) sought to install HTCB as a way to reduce these collisions while allowing for ease of maintenance operations within the narrow median.  Designers at Morrison Hershfield (MH), while familiar with traditional roadside barrier systems, conducted research on how to implement HTCB using AT’s _Design Bulletin #75/2012 _and _HTCB (and Rumble Strips) Practices and Guidelines_ presentation. The design had to consider many factors, such as horizontal and vertical geometry of each carriageway, superelevation, grade differences across the median, accommodating left-turn storage lanes, median openings and connections to existing bridgerail and strong-post W-beam.

Construction had its own unique challenges, working with a contractor who was relatively new to HTCB, and AT’s requirements for working on a very busy highway, as well as the learning curve associated with installing a proprietary product. Overall, the HTCB installation went smoothly as AT’s Project Manager, the designers, and contractor all worked together to complete the project.  The finished project is a 10 km section of highway with new HTCB that is aesthetically compatible and provides a higher level of safety than before.