ADEME: Turn Off Car Engine After 10 Seconds in Traffic, per Selectra
Drivers facing holiday traffic on October 31 and November 1, 2026, should switch off their engines during stops exceeding ten seconds to limit fuel costs, according to guidance from France’s environment agency ADEME reported by Selectra.
Fuel Consumption and Idle Costs in Traffic
Idling vehicles burn between 0.5 and 1 litre of fuel per hour, Selectra reported. Based on fuel prices recorded on October 28, 2026, keeping a motor running for an hour costs between 1.06 euros and 2.11 euros for E10 petrol, and between 1.19 euros and 2.39 euros for diesel.
For a cumulative thirty-minute stop during a multi-hour journey, turning off the engine prevents up to 0.53 to 1.06 euros in E10 expenses and 0.60 to 1.19 euros in diesel expenses. These figures represent the cost of burned fuel while stationary rather than net savings, as restarting the vehicle also consumes a small amount of energy.
Comparing Current Guidance With Past Official Stances
The ten-second threshold differs from earlier official benchmarks. In a 2016 response from the Ministry of Ecology, authorities cited a twenty-second threshold before restarting became more efficient than idling. The ADEME factsheet titled Clés pour agir en déplacement now advises shutting down the motor for any halt lasting longer than ten seconds.
| Duration of Idling | Fuel Burned | Estimated Cost (E10 ; Diesel) |
|---|---|---|
| 15 minutes | 0.125 to 0.25 L | 0.26 to 0.53 € ; 0.30 to 0.60 € |
| 30 minutes | 0.25 to 0.5 L | 0.53 to 1.06 € ; 0.60 to 1.19 € |
| 1 hour | 0.5 to 1 L | 1.06 to 2.11 € ; 1.19 to 2.39 € |
| 2 hours | 1 to 2 L | 2.11 to 4.23 € ; 2.39 to 4.77 € |
Stop-and-start technology automatically cuts engines in modern vehicles, but the system remains on standby in specific scenarios. Motors stay active when the engine remains cold or when windshield defogging is operating.
Traffic Conditions on the Toussaint Return
Bison Futé classified the return traffic toward Île-de-France as orange for Saturday, October 31, and Sunday, November 1, 2026, indicating difficult driving conditions. Traffic moving in jerky, stop-and-start pulses often involves stops shorter than ten seconds, making continuous engine operation appropriate.
Immobile queues, stationary toll booths, and accidents further ahead create longer delays where shutting down the motor makes a financial difference.