3309 - Driving on roadways laned for traffic.

     § 3309.  Driving on roadways laned for traffic.        Whenever any roadway has been divided into two or more     clearly marked lanes for traffic the following rules in addition     to all others not inconsistent therewith shall apply:            (1)  Driving within single lane.--A vehicle shall be        driven as nearly as practicable 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.            (2)  Three lane roadways.--Upon a roadway which is        divided into three lanes and provides for two-way movement of        traffic, a vehicle shall not be driven in the center lane        except when overtaking and passing another vehicle traveling        in the same direction when the center lane is clear of        traffic within a safe distance, or in preparation for making        a left turn, or where the center lane is allocated        exclusively to traffic moving in the same direction that the        vehicle is proceeding and the allocation is designated by        official traffic-control devices.            (3)  Lanes limited to specific use.--Official traffic-        control devices may be erected to restrict the use of        specified lanes to specified classes or types of traffic or        vehicles, including multioccupant vehicles or car pools, and        drivers of vehicles shall obey the directions of every such        device.            (4)  Prohibitions against changing lanes.--Official        traffic-control devices may be installed prohibiting the        changing of lanes on a section of roadway and drivers of        vehicles shall obey the directions of every such device.        Cross References.  Section 3309 is referred to in sections     1603, 3326 of this title.