Vehicle stopping distances never depend on:
- Your own reaction time.
- The time of day. ✓
- The condition of your vehicle's brakes.
- The condition and type of your vehicle's tires.
Answer: B. The time of day.
Stopping distance never depends on the time of day — the correct choice is the time of day.
Why this is the answer
The handbook breaks total stopping distance into three parts: perception distance, reaction distance, and braking distance. Reaction distance comes from your own reaction time, and braking distance is measured with good brakes on dry pavement at a given speed. So how quickly you notice and react, how well your brakes work, and how much grip the road and tires give all feed into the total. Nothing in that breakdown involves what hour it is; daylight or darkness is not one of the pieces that adds up to the distance your car covers before it stops.
Why the other answers are wrong
- A. Your own reaction time. — Your own reaction time is one of the three pieces of total stopping distance, since the handbook counts reaction distance as part of the total.
- C. The condition of your vehicle's brakes. — Brake condition is built into braking distance — the handbook's figure of about 158 feet at 50 MPH is given for a vehicle with good brakes.
- D. The condition and type of your vehicle's tires. — Tire condition and type are what connect the car to the pavement, so they belong with the road and weather conditions the handbook assumes when it quotes a braking distance.
Remember it
Picture stopping distance as three stacked blocks — see it, react to it, brake — and ask which block a clock could change. None of them.