When speed and size increase, how is braking distance affected?

• A. Decreases
• B. Remains the same
• C. INCREASES with vehicle SIZE and SPEED
• D. Varies unpredictably

Answer: (C)

Braking distance grows as speed increases and as vehicle size (mass) increases because more energy and momentum must be dissipated to stop. The faster you go, the more kinetic energy you carry, so the brakes have to work harder and longer to bring you to a halt. A heavier vehicle has greater momentum at the same speed, so the same braking force produces less deceleration, requiring a longer distance to stop. In practical terms, doubling speed doesn’t just double the stopping distance—it increases it more than proportionally, and adding weight makes stopping even more demanding. That’s why heavier, faster vehicles require more distance to stop and why you must increase following distance and reduce speed accordingly, especially in fire apparatus operations.