Lawful brakes must be able to stop a car traveling at 20 miles per hour within approximately 25 feet. This is a common legal requirement to ensure safety for pedestrians and drivers
. However, typical stopping distances in normal driving conditions, which include both thinking distance and braking distance, are generally around 40 feet (12 meters) at 20 mph on dry roads
. This total stopping distance accounts for the time it takes a driver to react plus the distance the car travels while braking. In summary:
- Legal brake stopping distance at 20 mph: about 25 feet (braking distance only)
- Typical total stopping distance at 20 mph (thinking + braking): about 40 feet (12 meters) under normal conditions
The legal requirement focuses on the braking capability of the vehicle alone, excluding thinking distance.
