Road safety: when to turn off your engine?

Original publication: 24/04/2026
Author : Commissioner Olivier Quisquater, Highway Police

In this period of overpriced fuel, it's a good time to remember that regulations require you to turn off your engine when you're stationary. But it's not that simple, because several regulations coexist and don't say quite the same thing.

First of all, you have the Highway Code, which states the following: "It is forbidden for any driver to proceed, in neutral, to repeatedly accelerate the engine. Drivers should also be careful not to leave the engine running in neutral unless necessary. »

Not leaving the engine running in neutral can be a big problem, with a small grey area that requires reason. But for example, at a level crossing, where the wait can be quite long, it's safe to say that you have to turn off your engine. The same goes for someone who is running an errand in a parked position. As for the notion of necessity, it is not defined, but certainly avoid anything that is purely for personal convenience, such as heating or cooling the vehicle.

It is true that recent cars have a device that shuts off the engine when you go into neutral, which allows you to comply with the regulations. But it only works for short downtime. Sometimes you will have to turn off the engine yourself as soon as it lasts, because the automatic device will restart the engine on its own after a generally very short time (often less than 60 seconds), especially to preserve the battery.

In addition to the Highway Code, we also have regional regulations, which are slightly different.

Thus, the Walloon rule provides that: when a vehicle is stationary in a place where it is not prohibited to stop or park a vehicle pursuant to Article 24 of the Highway Code, the driver directly switches off the vehicle's engine.

So, here, it does not apply to situations where you are always taking part in traffic, such as waiting at a level crossing, but only to situations where you have pulled out of traffic.

A similar text exists for Flanders, while in Brussels they are satisfied with the rule of the Highway Code, at least for the time being.

That said, all of this is relatively easy to understand: when you're stationary for more than a few seconds, it's a good idea to turn off your engine, whether it's done automatically by the car itself or by yourself. In any case, it is better to turn off the engine when you are going to stay stationary for more than 10-15 seconds.