What is not included in the stopping sight distance?
2 Answers
Stopping sight distance does not include the starting distance. Relevant information is as follows: 1. Definition: Stopping sight distance refers to the shortest driving distance required for a vehicle to stop when encountering an obstacle ahead on the same lane. The stopping sight distance can be broken down into three parts for study: reaction distance, braking distance, and safety distance. 2. The stopping sight distance consists of three parts: the distance S1 traveled during the driver's reaction time, the distance S2 traveled from the start of braking until the vehicle comes to a complete stop (braking distance), plus the safety distance S (5~10m). The minimum safety distance that should be maintained between the vehicle and the obstacle after the vehicle has completely stopped. It is generally 5~10m. Due to its small value, it is already considered in the reaction distance during calculation and is not separately accounted for.
Stopping sight distance does not include the process of a vehicle accelerating from a standstill to its maximum speed; it only covers the total distance from when the driver perceives an obstacle, reacts, and comes to a complete stop. For example, when you see an obstacle ahead, the distance from the moment you react and apply the brakes until the vehicle stops is what stopping sight distance concerns; it does not include the gradual acceleration when starting. In road design, this standard ensures sufficient space to handle sudden situations but overlooks factors like turns, slopes, or slippery surfaces. Therefore, drivers should develop the habit of observing ahead, especially at high speeds or in poor weather conditions, maintaining a distance far greater than the theoretical value to avoid rear-end collisions.
