Delaware Code
Subchapter VIII. Speed Restrictions
§ 4171. Minimum speed.

(a) No person shall drive a motor vehicle at such a slow speed as to impede the normal and reasonable movement of traffic except when reduced speed is necessary for safe operation or in compliance with law.
(b) A minimum speed limit, below which no person shall drive a vehicle except when necessary for safe operation or in compliance with law, may be displayed on appropriate traffic-control devices.