A nationwide 55-miles-per-hour speed limit was enacted in this year.
1975
1974
1972
1970
1974. Previously, states were allowed to set their own speed limits, but in a 1974 highway bill, President Nixon set a nationwide speed limit of 55 miles-per-hour. The speed limit was designed to save fuel during the oil embargo of the US by Arab members of OPEC (Organization of Petroleum Exporting Countries.