Abstract: A security barrier system for use with a trafficable surface and a site requiring protection from advancing vehicles includes a composite bed system having a plurality of elevations and comprising a first layer beneath a second layer. The first layer includes a deformable material configured to collapse when subjected to vehicle loads, and the second layer includes a pedestrian cover surface over the deformable material that conceals the deformable material. The pedestrian cover surface is configured to support pedestrian traffic over the deformable material without permanently collapsing the deformable material and to collapse along with the first layer when subjected to vehicle loads. A structure beyond the bed system is provided to resist the impact of a vehicle that has traversed the bed system.