Highway Design for Safety

Early in the 1900's, as the number of automobiles increased and the quality improved, there came a public demand for all weather roads -roads that would have at least acceptable surfaces in any of the worst weather.Everybody wanted his road fixed so there was a need to spread the tax dollars as thin as possible and still accomplish the all weather surface.W hen the driver got his all weather surface, it was thought that it was as much as he could expect.As far as safety was concerned, he was pretty much on his own.Road design for safety was generally considered too expensive.Early design hugged the ground with profiles and put sharp curves in to save a little excavation here and there.Excavation was expensive in the days when slip scoops and mule teams were used.Ditches were built close to pavement edges and bridges were quite narrow.Too many things were done to spread the tax dollars.Statistics will bear this out as fatality rates per miles traveled were much higher in the 1930's than now.At present there is a new emphasis on safety.Now about every body is out of the mud with all weather roads.W e are more affluent.W e afford more and better cars.Hence, we can afford safer and better roads.W e are in a period of design where the accent is on safety.Safety should no longer be spared to spread road tax dollars.It is better that many wait for a safe road rather than everyone getting half safe roads a little sooner.Some of the new safety features being accepted are: (1) limited access (2) dual lane highways (3) median barriers (4) long sight distance by flat grades, flat curves, both vertical and horizontal, and (5) highway lighting.