Current design practice recommends that concrete barrier not be placed on slopes steeper than 10H:1V. This has limited the placement of concrete barriers to narrow, flat, paved medians or at the edge of the shoulder. Finite element analyses were used to determine critical barrier offsets for placement on slopes and to assess impact performance of both cast-in-place and free-standing concrete barrier configurations at these critical offsets. The research determined that cast-in-place F-shape barrier and precast free-standing X-bolt F-shape barrier are suitable for placement on roadside and median foreslopes of 6H:1V or less. Increasing the maximum slope on which concrete median barriers can be placed will allow selected installations to be placed further from the travelway, which in turn will most likely lead to a reduction in barrier impact frequency and severity.
N.M. Sheikh, R.P. Bligh, W.L. Menges. Crash Testing and Evaluation of F-Shape Barriers on Slopes. Research Report. 0-5210-3. Texas A&M Transportation Institute, College Station, TX. March 2008.