What does 追越し (oikoshi) mean? Overtaking in Japan

Legal definition: "changing course" is the key

The Act defines oikoshi as "a vehicle, having caught up with another vehicle, changing its course, passing alongside that vehicle and moving in front of it". The Rules of the Road (教則) put it as "changing course and moving in front of the vehicle ahead".

There are three elements: (1) catching up, (2) changing course, (3) passing alongside and getting in front. Without (2) it is oinuki. For example, on a road with two lanes each way, staying in your lane and getting ahead of a car in the left lane is oinuki.

Spelling and reading: 追越し (おいこし / oikoshi). Test questions often write it 「追い越し」.

How to overtake

"Either side is fine if it is safe" is False.

• As a rule, pass on the right of the vehicle ahead (Article 28(1))
• If the vehicle ahead has moved to the center of the road (right edge on a one-way road) to turn right, pass on its left (Article 28(2))
• Overtake streetcars on the left (unless the tracks run along the left edge of the road)
• On roads with lanes (車両通行帯), use the lane immediately to the right and return promptly when done
• Signal about 3 seconds before changing course. When being overtaken, do not speed up until the other car has finished; if there is not enough room, keep as far left as possible

Where overtaking is banned (Article 30)

In these places you may not change course or pass alongside to overtake cars or mopeds. Overtaking bicycles and other light vehicles (軽車両) is not banned (mopeds, 原付, are not part of this exception).

When you must not start overtaking, and test traps

Wherever you are, do not start overtaking when the vehicle ahead is overtaking a motor vehicle (double overtaking), when it is about to move right to turn, when you would obstruct oncoming traffic, or when the car behind is overtaking you (Article 29 and the Rules).

Common False statements: "Overtaking a car that is overtaking a moped is double overtaking" (only when it is overtaking a motor vehicle); "overtaking is banned in tunnels even with lanes"; "steep uphill slopes are no-overtaking places". The test likes to compare these with no-stopping places (steep slopes both ways, tunnels always).

Practice the exceptions in your language

Since October 2025 the knowledge test has 50 True/False questions in 30 minutes; you need 45 correct. Overtaking has many exceptions (priority roads, lanes, light vehicles). menkyopass lets you practice with English explanations (the first mock test and three topics are free).

Practice questions using this term

• Where this sign is posted, you may overtake as long as you do not cross into the right half of the road.
• You must not overtake or pass a vehicle that is displaying the elderly driver mark.
• Overtaking means changing course and moving ahead of a moving vehicle in front of you.
• At a pedestrian crossing and within 30 meters before it, not only overtaking but also passing is prohibited.
• At an intersection and within 30 meters before it, you must not overtake, even when you are driving on a priority road.
• Overtaking is prohibited at a railroad crossing and within 30 meters before it.
• Near a bend in the road, you may overtake only when you have a clear view.
• A steep uphill slope is a place where overtaking is prohibited.
• Inside a tunnel, overtaking is prohibited whether or not there are vehicle traffic lanes.
• When the vehicle ahead is trying to overtake a motorized bicycle (moped), overtaking that vehicle is prohibited as double overtaking.

FAQ

Related guides

• Overtaking Rules in Japan: No-Overtaking Zones and Passing
• What does 追抜き (oinuki) mean? Passing vs overtaking
• 追越し vs 追抜き: Overtaking vs Passing in Japan's Test
• What does 車両通行帯 (sharyō tsūkōtai) mean? Traffic lanes

Sources (in Japanese)

• e-Gov法令検索「道路交通法」（第2条第1項第21号・第27条〜第30条）
• 警察庁「交通の方法に関する教則」（令和6年11月13日現在・全文PDF）第5章第6節 追越しなど