Delaware Code Title 21. Motor Vehicles § 4122. Driving on roadways laned for traffic

(1) A vehicle shall be driven as nearly as practicable entirely within a single lane and shall not be moved from such lane until the driver has first ascertained that such movement can be made with safety.

(2) Upon a roadway which is divided into 3 lanes for 2-way traffic, a vehicle shall not be driven in the center lane except when overtaking and passing another vehicle where the roadway is clearly visible and such center lane is clear of oncoming traffic within a safe distance, or in preparation for a left turn or where such center lane is at the time allocated exclusively by traffic-control devices to traffic moving in the direction the vehicle is proceeding.

(3) Traffic-control devices may be erected directing specified traffic to use a designated lane or designating those lanes to be used by traffic moving in a particular direction regardless of the center of the roadway, and drivers of vehicles shall obey the directions of every such traffic-control device.

(4) Traffic-control devices may be installed prohibiting the changing of lanes on sections of roadway and drivers of vehicles shall obey the directions of every such device.