Effect of 55.mph speed limit on average speeds of freeflowing automobiles on an interstate bridge in West-Virginia. Presented at the 54th Annual Meeting of the Transportation Research Board, Washington, January 1975.

A decline in mean vehicle speeds on an interstate bridge from 61.0 mph in 1973 to 54.5 mph in 1974 is reported. This effect is attributed to the nationwide lowering of speed limits to 55. mph. Standard deviation of the distribution also was reduced from 9.3 mph to 6.0 mph. It is suggested that this effect was a factor contributing to the reduction in accidents after limits were reduced.