Testing. Although not tested to resist the effects of a perpendicular impact, a cable,
W-beam, or box-beam guardrail, designed for highway use, should effectively deflect and,
possibly, immobilize lightweight vehicles. They are specifically designed to deflect the energy
of larger vehicles with an angled impact of less than 25 degrees (normal impact angle for
highway design and most likely to produce vehicle rollover at high speeds).
Heavy Equipment Tires
Description. Heavy equipment tires, half-buried in the ground and tamped to hold
them rigid, can be effective vehicle barriers (Figure 30). Use tires that are 7 to 8 feet (2.1 to 2.4
m) in diameter. Heavy equipment tires can usually be obtained locally from salvage operations
for the cost of hauling them away.
Heavy Equipment Tire Barrier
Testing. Buried equipment tires were tested using a 3,350-pound (1,523-kg) vehicle
traveling at 51 mph (82 kph). The vehicle penetrated the barrier 1-foot (0.3-m). The tires used
were 36 ply, 8 feet in diameter (2.4 m), and weighed 2,000 pounds (909 kg) each.