61-8-303. Speed restrictions. (1) Except as provided in 61-8-309, 61-8-310, 61-8-312, and subsection (2) of this section, the speed limit for vehicles traveling:
     (a) on a federal-aid interstate highway outside an urbanized area of 50,000 population or more is 75 miles an hour at all times and the speed limit for vehicles traveling on federal-aid interstate highways within an urbanized area of 50,000 population or more is 65 miles an hour at all times;
     (b) on any other public highway of this state is 70 miles an hour during the daytime and 65 miles an hour during the nighttime.
     (2) The speed limit for vehicles traveling on U.S. highway 93 between the Canadian and Idaho borders is 65 miles an hour at all times. The speed limit imposed by this subsection ceases to be effective if U.S. highway 93 is upgraded to a continuous four-lane highway.
     (3) A vehicle subject to the speed limits imposed in subsection (1) traveling on a two-lane road may exceed the speed limits imposed in subsection (1) by 10 miles an hour in order to overtake and pass a vehicle and return safely to the right-hand lane.
     (4) Subject to the maximum speed limits set forth in subsections (1) and (2), a person shall operate a vehicle in a careful and prudent manner and at a reduced rate of speed no greater than is reasonable and prudent under the conditions existing at the point of operation, taking into account the amount and character of traffic, visibility, weather, and roadway conditions.
     (5) When no special hazard exists that requires lower speed for compliance with subsections (1) and (2), the speed of a vehicle not in excess of the limits specified in this section or established as authorized in 61-8-309 through 61-8-311 and 61-8-313 is lawful, but a speed in excess of 25 miles an hour in an urban district is unlawful.
     (6) "Daytime" means from one-half hour before sunrise to one-half hour after sunset. "Nighttime" means at any other hour.
     (7) The speed limits set forth in this section may be altered by the transportation commission or a local authority as authorized in 61-8-309, 61-8-310, 61-8-313, and 61-8-314.

     History: En. Sec. 41, Ch. 263, L. 1955; amd. Sec. 1, Ch. 190, L. 1967; amd. Sec. 55, Ch. 316, L. 1974; R.C.M. 1947, 32-2144; amd. Sec. 1, Ch. 173, L. 1989; amd. Sec. 6, Ch. 75, L. 1995; amd. Sec. 1, Ch. 78, L. 1995; amd. Sec. 2, Ch. 287, L. 1995; amd. Sec. 3, Ch. 473, L. 1997; amd. Sec. 2, Ch. 43, L. 1999.