Vehicle Barriers and Crash Ratings: K-Ratings, ASTM and Standoff
Vehicle barriers exist to stop a moving vehicle, and the question a designer has to answer is not "is this strong" but "how much vehicle, at what speed, stopped within what distance". Crash ratings exist to answer that precisely, and the exam expects you to recognize the vocabulary. The Rating Systems The older Department of State K-rating used a 15,000 lb truck and rated by impact speed: K4 — 30 mph K8 — 40 mph K12 — 50 mph To pass, the vehicle's load bed could penetrate no more than one metre past the barrier. That system was superseded by ASTM F2656 , which is more expressive because it states the vehicle class as well as the speed. A designation such as M50-P1 reads as: M for medium-duty truck, 50 for 50 mph, P1 for the tightest penetration class — one metre or less. Vehicle classes include small passenger cars (C), pickups (PU), medium trucks (M) and heavy goods vehicles (H). Penetration ratings run P1 through P4, with P1 the least pene...