Joe G. Tom

Durable roadside protective structures for low-volume roads

Data compilations on accidents nationwide show that 30% of all traffic fatalities and 16% of all injuries occur when a vehicle goes into a ditch or strikes a fixed obstacle on the roadside. Highway traffic barriers and crash cushions are not economical for use on low-volume roads, even though they could be helpful in reducing fatalities and injuries. Sand-filled barrels and metal barriers that undergo controlled deformation are relatively expensive and require significant investments in placement, inspection, maintenance, and repair. A crash cushion design based on scrap tires encased in foamed, fiber-reinforced concrete is being developed and can provide a versatile, low-maintenance safety barrier that is also resistant to vandalism. The composite scrap tire–and–concrete protective barrier uses a skeleton of scrap tires as an attachment point that can serve to lift, place, and anchor a mass of foamed, fiber-reinforced concrete in place on the roadside. The foamed, fiber-reinforced concrete crushes like wood under impact from tools or projectiles, so the modules are difficult to vandalize and can survive scrapes from graders or snow removal equipment. Module array can be developed on the basis of weight distribution in sand-filled barrel arrays. Potential uses for the barrier modules include protection of bridge piers, bridge railings, and obstacles on curves. The durability and economy of these units make them a practical option for use in improving safety on low-volume roads, especially in remote areas.