Chapter 2: Speed Limits

Controlling a vehicle’s speed is one of the most critical responsibilities a driver has. Exceeding the speed limit is a common factor in traffic crashes, but driving too slowly for conditions can be equally dangerous. Understanding Delaware’s speed laws, including the basic rule to always drive at a speed that is reasonable and prudent for the current conditions, is essential for passing the driver’s exam and for the safety of everyone on the road.

The Basic Speed Law

Delaware law requires that a person must not drive a vehicle at a speed greater than is reasonable and prudent under the conditions. This is known as the Basic Speed Law. It means the posted speed limit is the absolute maximum speed permitted under ideal conditions, such as on a dry, clear day with light traffic.

Drivers must always adjust their speed based on the actual conditions of the road, traffic, and weather. If conditions are poor, a driver must slow down to a speed that is safe, even if it is below the posted limit. For example, during heavy rain, fog, or snow, visibility is reduced and pavement is slippery, requiring a slower speed. Similarly, in heavy traffic, on narrow roads, or in construction zones, the safe and legal speed may be much lower than what is posted. Violating the Basic Speed Law can result in a ticket, even if the driver was not exceeding the posted speed limit.

Common Mistake:
Assuming it is always legal to drive at the posted speed limit. The posted number is a maximum for perfect conditions. If rain is pouring down, driving 55 mph in a 55 mph zone is both unsafe and illegal under the Basic Speed Law.