Over the last 25 years experience with highway crashes has shown that there has been an obvious interest to improve the impact attenuation features of the highway furniture and off-road areas. In the past it appears that the road was built for long life, with little concern for the errant vehicle that left the paved surface of the roadway. Today, guard-rails and other protective devices are placed in areas of high probability of potential accidents or structures, such as sign posts, have been significantly modified for crash protection.
Abstract