§ 73.17  DRIVING ON ROADWAYS LANED FOR TRAFFIC.
   All vehicles operated on any roadway which has been clearly marked with lanes for traffic shall be driven as nearly as practical entirely within a single lane and shall not be moved from the lane until the driver has first ascertained that the movement can be made with safety.
(1973 Code, § F-V-17)  Penalty, see § 10.99