A. The governing bodies of counties, cities, and towns may adopt ordinances not in conflict with the provisions of this title to regulate the operation of vehicles on the highways in such counties, cities, and towns. They may also repeal, amend, or modify such ordinances and may erect appropriate signs or markers on the highway showing the general regulations applicable to the operation of vehicles on such highways. The governing body of any county, city, or town may by ordinance, or may by ordinance authorize its chief administrative officer to:
1. Increase or decrease the speed limit within its boundaries, provided such increase or decrease in speed shall be based upon an engineering and traffic investigation by such county, city or town and provided such speed area or zone is clearly indicated by markers or signs;
2. Authorize the city or town manager or such officer thereof as it may designate, to reduce for a temporary period not to exceed sixty days, without such engineering and traffic investigation, the speed limit on any portion of any highway of the city or town on which work is being done or where the highway is under construction or repair;
3. Require vehicles to come to a full stop or yield the right-of-way at a street intersection if one or more of the intersecting streets has been designated as a part of the primary state highway system in a town which has a population of less than 3,500.
B. No such ordinance shall be violated if at the time of the alleged violation the sign or marker placed in conformity with this section is missing, substantially defaced, or obscured so that an ordinarily observant person under the same circumstances would not be aware of the existence of the ordinance.
C. No governing body of a county, city, or town may provide penalties for violating a provision of an ordinance adopted pursuant to this section which is greater than the penalty imposed for a similar offense under the provisions of this title.
D. No county whose roads are under the jurisdiction of the Department of Transportation shall designate, in terms of distance from a school, the placement of flashing warning lights unless the authority to do so has been expressly delegated to such county by the Department of Transportation, in its discretion.
Code 1950, §§ 46-198, 46-200; 1956, c. 134; 1958, c. 541, § 46.1-180; 1960, c. 172; 1972, c. 522; 1984, c. 345; 1989, c. 727.