Gaimen50-question practice tests in the real exam formatBus-Only (専用通行帯) vs Bus-Priority (優先通行帯) Lanes in Japan
Updated: 2026-10
A bus-only lane (専用通行帯, sen'yō tsūkōtai) may be used only by the designated vehicles plus small special vehicles, mopeds (原付) and light vehicles; ordinary cars generally may not enter. A bus-priority lane (優先通行帯, yūsen tsūkōtai) is open to ordinary cars, but when a route bus approaches from behind you must leave it promptly. The knowledge test likes false statements such as "a priority lane is the same as a bus-only lane" or "mopeds cannot use a bus-only lane".
Legal definitions and comparison table
Exclusive lanes are designated by signs and road markings under Article 20(2) of the Road Traffic Act. The Order on Road Signs defines this as designating a lane that specific vehicles must use, while other vehicles (except small special vehicles, mopeds and light vehicles) must use the other lanes.
Priority lanes are governed by Article 20-2. On a road with a route-bus priority lane, an automobile (other than a route bus) must not enter it if congestion would prevent it from leaving when a bus approaches, and if it is already in the lane when a bus approaches from behind, it must promptly move out so as not to disrupt the bus.
| Point | Bus-only lane (専用通行帯) | Bus-priority lane (優先通行帯) |
|---|---|---|
| Legal basis | Road Traffic Act Art. 20(2) | Road Traffic Act Art. 20-2 |
| Ordinary cars (普通自動車) | Generally may not use it | May use it |
| Small special vehicles, mopeds, light vehicles | May use it | May use it |
| When a route bus comes from behind | (ordinary cars are not in it) | Leave the lane promptly |
| When traffic is too heavy to get out | (same as above) | Do not enter in the first place |
| Moving to the left edge to turn left | Allowed | Allowed |
| Unavoidable cases such as roadworks | Allowed | Allowed |
Bus-only lane: ordinary cars stay out
The National Police Agency's Rules of the Road say that where a route-bus exclusive lane is designated, "vehicles other than small special vehicles, mopeds and light vehicles must not travel in that lane". Ordinary cars and motorcycles may not drive in it.
The exceptions are when you move to the right edge, center or left edge of the road to turn, and unavoidable cases such as roadworks (Article 20(3); Rules of the Road). For example, you may enter a bus-only lane on the far left in order to turn left.
Do not confuse it with the "ordinary bicycle exclusive lane" (普通自転車専用通行帯). There, only specified small motorized bicycles (特定小型原動機付自転車) and light vehicles may travel. Unlike a bus-only lane, ordinary mopeds (一般原付) may not use it.
Bus-priority lane: you may enter, but leave when a bus comes
The big difference is that ordinary cars may use a priority lane. However, an automobile in the lane must promptly leave it when a route bus approaches from behind.
If traffic is so heavy that you might not be able to get out when a bus comes, you must not enter the priority lane in the first place. Remember it as "enter only when you can get out right away", not "free to enter".
Here too, moving to the edge or center of the road to turn, and unavoidable cases such as roadworks, are exceptions (proviso to Article 20-2(1); Rules of the Road).
Reading the signs, markings and time limits
Both lanes are shown with white-on-blue regulatory signs and with markings painted on the road. Always check whether the sign or marking says 専用 (exclusive) or 優先 (priority).
Often the hours of the restriction are shown as numbers. Those numbers limit when the rule applies; outside those hours there is no restriction, so ordinary cars may use even a bus-only lane.
How to choose lanes normally on roads with three or more lanes each way is covered in our article on traffic lanes (車両通行帯).
Tricky test questions and answers
These are question types on the knowledge test. Both are false.
Example 1: "路線バス等の「専用通行帯」は、小型特殊自動車、原動機付自転車、軽車両であっても通行してはならない。" (Even small special vehicles, mopeds and light vehicles must not use a route-bus exclusive lane.) Answer: False (×). Small special vehicles, mopeds and light vehicles may use it. Ordinary cars may also use it to turn left or in unavoidable cases such as roadworks.
Example 2: "路線バス等の「優先通行帯」は専用通行帯と同じ意味であり、普通自動車は通行してはならない。" (A route-bus priority lane means the same as an exclusive lane, so ordinary cars must not use it.) Answer: False (×). Ordinary cars may use a priority lane, but must promptly leave it and give way when a route bus approaches from behind.
Also watch for rewordings such as "in a priority lane you may keep driving even when a bus comes" (false: leave promptly) and "you may not enter a bus-only lane even to turn left" (false: you may, to turn).
Practice lane questions in your language
専用 and 優先 are a classic case where one Japanese word flips the answer. menkyopass's license conversion (外免切替) drill lets you practice sign and lane questions with explanations in Vietnamese, English, Chinese and Japanese (the first mock test and 3 topics are free; all questions are a one-time ¥2,980).
Practice questions using this term
FAQ
Q. Can I ride a moped (原付) in a bus-only lane?
A. Yes. Route-bus exclusive lanes are open to small special vehicles, mopeds and light vehicles. Ordinary mopeds may not use an ordinary-bicycle exclusive lane, though.
Q. May I enter a bus-only lane to turn left?
A. Yes. When you move to the left edge of the road to turn, you may travel in the exclusive lane.
Q. What if a bus comes up behind me in a priority lane?
A. Leave the lane promptly so you do not disrupt the bus. If traffic is so heavy you might not get out, you should not enter the priority lane at all.
Q. Can I use a bus-only lane outside its hours?
A. If hours are shown, the restriction does not apply outside them, so ordinary cars may use the lane. Always check the numbers on the sign.