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IdlingJapan

Learn traffic rules with clear explanations and visual examples in our illustrated book, designed to make studying simple and engaging.

Traffic signs
Traffic rules
Japan

89. Idling

Idling means allowing a vehicle's engine to continue running while the vehicle is stationary and the engine is not being used to move the vehicle. This may occur while waiting, parking, loading or unloading or before beginning a journey.

Unnecessary idling consumes fuel and produces exhaust emissions, air pollution and noise. Many countries or local authorities restrict prolonged or unnecessary idling, although exceptions may apply when the engine is required for safety, technical equipment or another necessary purpose.

A stationary vehicle with its engine running is idling. (Volkswagen Golf)
Wikimedia.org • Spacekid • CC0
What is idling?

Idling means keeping a vehicle's engine running while the vehicle remains stationary and the engine is not being used to propel it.

Why should unnecessary idling be avoided?

Unnecessary idling uses fuel, produces exhaust emissions and creates noise without moving the vehicle.

Is idling illegal everywhere?

No. Rules differ between countries and local authorities. Some prohibit unnecessary idling generally, while others restrict it only in particular locations or circumstances.

Does an idling engine still produce exhaust emissions?

Yes. A combustion engine continues to produce exhaust gases while running even though the vehicle is not moving.

Does idling use fuel?

Yes. A combustion engine consumes fuel while it remains running, even when the vehicle is stationary.

Should you leave the engine running while waiting for someone?

Where it is safe and legal to switch the engine off, unnecessary prolonged idling should generally be avoided. Local rules may specifically require the engine to be switched off.

Is waiting at a red traffic light the same as parking with the engine idling?

No. A vehicle temporarily prevented from moving by traffic conditions is different from a vehicle voluntarily parked or waiting. The rules concerning engine shutdown may therefore differ.

Can an engine remain running when vehicle equipment needs power?

Some laws provide exceptions when the engine is genuinely required to operate refrigeration, hydraulic equipment, emergency equipment or another essential system. The precise exceptions depend on local law.

Should you rev the engine while stationary?

Unnecessary engine revving should be avoided because it increases noise, fuel consumption and emissions. It may also be specifically prohibited by local traffic or noise regulations.

Do electric vehicles idle?

Not in the conventional combustion-engine sense. An electric vehicle can remain stationary while switched on without an internal-combustion engine running, although electrical systems such as heating or air conditioning may still consume energy.

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