Delaware Code Title 21. Motor Vehicles § 4331. When lighted lamps are required

(a) Every vehicle upon a highway within this State at any time from sunset to sunrise, or during fog, smoke, rain or when windshield wipers are in use because of weather conditions or at any other time when, due to insufficient light or unfavorable atmospheric conditions, persons and vehicles on the highway are not clearly discernible at a distance of 1,000 feet ahead shall display lighted lamps and illuminating devices, exclusive of parking lamps, as hereinafter respectively required for different classes of vehicles, subject to exceptions with respect to parked vehicles.

(b) The portion of subsection (a) of this section criminalizing the failure to display lighted lamps and illuminating devices when windshield wipers are in use because of weather conditions shall constitute a secondary offense in that no person shall be stopped by a police officer for that failure alone.