For a semi traveling at 20 mph, what is the required stopping distance?

To determine the required stopping distance for a semi traveling at 20 mph, it's important to consider factors such as perception time, reaction time, and braking distance. The formula for stopping distance combines these elements and is typically calculated with the understanding that factors such as speed and the vehicle's weight play a significant role.

For vehicles, a rough estimate for stopping distance can be calculated using the formula: Stopping Distance = (Speed in mph x Reaction Time) + (Speed in mph x Speed in mph) / 20. Given that a reasonable reaction time is about 1.5 seconds, for a semi at 20 mph, the braking distance can roughly be estimated.

At 20 mph, factoring in average stopping time and distance gives a combined total stopping distance around 50 feet. This includes the distance covered during the driver’s reaction time and the distance needed to come to a complete stop. The option indicating 50 feet aligns with standard estimates for stopping distances at that speed, taking into account average reaction and braking performance for a truck of that size and type.

Understanding these calculations and relationships contributes to safe driving practices and ensuring vehicles can stop adequately in various conditions.