What factor is considered when determining braking distances for heavy vehicles?

When determining braking distances for heavy vehicles, vehicle weight and speed are critical factors. Heavier vehicles typically require longer distances to stop due to their mass, which results in greater momentum at a given speed. This means that as the weight of the vehicle increases, the stopping distance also increases, making it essential for drivers of heavy vehicles to be aware of their vehicle's weight and how it impacts braking performance.

Additionally, speed plays a significant role; as a vehicle travels faster, the kinetic energy increases, which in turn requires a longer distance to bring the vehicle to a stop. The relationship between speed and stopping distance is generally quadratic, meaning that even small increases in speed can result in significant increases in stopping distance.

Considering these two factors together—weight and speed—provides a comprehensive understanding of the dynamics involved in deceleration and stopping for heavy vehicles, highlighting the importance of accounting for both when planning and executing safe driving behaviors.