While Western
states have allowed it for more than 50 years;[
citation needed] eastern states amended their traffic laws to allow it in the 1970s as a fuel-saving measure in response to motor fuel shortages in
1973 and
1979. All 50 states, the
District of Columbia,
Guam, and
Puerto Rico have allowed right turns on red since 1978, except where prohibited by a sign or where right turns are controlled by dedicated
traffic lights. (In June 1978, Maryland became the last state to allow right turns on red.
[2] Right turns on red became legal in the District of Columbia in November 1978.
[3])