Sharing the road
An average passenger vehicle at 55 mph can stop within 300 feet. How much room can a large vehicle need at the same speed?
- Up to 400 feet. Correct answer
- About the same, 300 feet.
- Up to 500 feet.
Why
Same speed, a hundred feet more road. The handbook puts an average passenger vehicle at 300 feet to stop from 55 mph and a large vehicle at up to 400 feet, and it adds the part drivers forget: weight and speed both stretch that distance, so a loaded truck needs more room than an empty one. That gap is the reason for the rule you should actually change your behavior for, which the handbook states as a consequence rather than advice: do not pull in front of a large vehicle and then slow abruptly or stop, because it cannot shed that speed in time and ends up in your back bumper. Five hundred feet is a real number in the handbook, but it is where you dim your high beams for an oncoming vehicle.
Where this comes from
California Driver's Handbook, June 2025 edition. The correct answer is Up to 400 feet.
The rule behind this one
Sharing the road in California goes through the whole topic, with the page of the California Driver's Handbook behind every rule.
More on sharing the road
- The large truck ahead of you swings out to the left as it comes up to a corner. What is the safest reading of that move?
- When may you overtake and pass a light rail vehicle or a streetcar on its left side?
- Who is required to wear a helmet when riding a bicycle in California?
- You are riding a bicycle after dark. From how far away must the white light of your front lamp be visible?