Speed and Following Distance — 5 Practice Questions
Speed questions start from a principle rather than a number: a maximum speed binds you whether or not a sign is posted, and an empty road never raises it. What the statutory limit actually is depends on the type of road you are on.
The second axis is distance. Stopping distance is reaction distance plus braking distance, and braking distance grows with the square of speed, not in proportion to it — answering "twice the speed, twice the braking distance" is a lost mark. What "slow down" (徐行) legally means, a speed from which you can stop immediately, and following distance belong to the same topic.
Two wording traps sit on top of the physics. The first is a sentence that says "braking distance" where it means "stopping distance", or the reverse: they are different quantities and the test swaps them on purpose, so identify which one is named before you judge the claim. The second is conditions. The same speed needs more room on a wet surface, on a downhill, and with a heavy load, so a statement that ties one fixed distance to one speed with no conditions attached is usually the false one.
The five questions below cover all of it.
The five questions
Total stopping distance is the reaction distance plus the braking distance, and both grow as speed increases.
Show the answer and explanation
Answer True
Explanation Higher speed means you travel further before braking takes effect and need more distance to stop.
Basis in law 教則(速度と停止距離)
On a wide, empty road you may drive at whatever speed you feel is safe.
Show the answer and explanation
Answer False
Explanation False. The posted or statutory maximum still binds you, however empty the road.
Basis in law 道路交通法 第22条
You must keep enough distance from the vehicle ahead to stop safely if it brakes suddenly.
Show the answer and explanation
Answer True
Explanation Maintaining a safe following distance (車間距離) is a legal duty; it must be long enough to stop without colliding if the car ahead brakes hard.
Basis in law 道路交通法 第26条 / Road Traffic Act Art. 26
On a wet or icy road, your stopping distance is the same as on a dry road if you drive at the same speed.
Show the answer and explanation
Answer False
Explanation False. A slippery surface lengthens the braking distance considerably, so you must slow down and increase your following distance.
Basis in law 交通の方法に関する教則(悪条件での運転)
Driving much too slowly without good reason can obstruct traffic and is not appropriate.
Show the answer and explanation
Answer True
Explanation Needlessly slow driving impedes the flow and can be unsafe; keep a reasonable pace for conditions.
Basis in law 教則(速度)