Chapter 2: Speed Limits

Controlling a vehicle’s speed is one of the most fundamental and critical responsibilities of a driver. Speed directly affects the time a driver has to react to hazards and the severity of any crash that occurs. Understanding and obeying speed laws is not just about avoiding tickets; it is about protecting one’s own life, the lives of passengers, and the safety of everyone else on the road.

The Basic Speed Law

Texas law includes a “Basic Speed Law,” a fundamental principle that governs safe driving speeds. This law states that a driver must not operate a vehicle at a speed greater than is reasonable and prudent under the existing conditions. The posted speed limit is the absolute maximum speed permitted under ideal conditions, such as clear, dry weather and light traffic.

This means a driver can be cited for speeding even if they are driving at or below the posted limit if conditions make that speed unsafe. Factors that require a driver to reduce their speed below the posted limit include:

• Rain, fog, snow, sleet, or ice, which reduce tire traction and visibility.
• Heavy traffic, which decreases the space between vehicles.
• Darkness or low-light conditions that limit how far a driver can see ahead.
• Approaching sharp curves, hillcrests, or intersections.
• Driving on narrow or winding roads.
• The presence of pedestrians, bicyclists, or road hazards.

Common Mistake:
Many drivers assume that if they are driving at the posted speed limit, they are driving legally. However, if it is raining heavily and visibility is poor, driving 70 mph on the highway—even if that is the posted limit—is unsafe, unreasonable, and a violation of the Basic Speed Law.

Texas Default Speed Limits

When a specific speed limit sign is not posted, Texas law establishes statutory, or “prima facie,” speed limits. Drivers are responsible for knowing these default limits.