What factors are included in "total stopping distance"?

Total stopping distance is the distance a vehicle travels from the moment a driver perceives a need to stop until the vehicle comes to a complete stop. This distance is composed of two primary components: reaction distance and braking distance.

Reaction distance refers to the distance a vehicle travels during the time it takes for the driver to react and begin applying the brakes after recognizing a hazard. This is influenced by the driver's alertness and perception time, as well as the vehicle's speed.

Braking distance is the distance it takes for the vehicle to stop once the brakes have been applied. This distance can vary based on several factors including vehicle speed, road conditions, and brake efficiency.

Thus, the correct answer incorporates both reaction distance and braking distance as the key components that together define total stopping distance.