Start-stop system
Automatically shuts the engine off at stops and restarts it when you release the brake.
A start-stop system switches the engine off when you come to a stop, at a red light for example, and restarts it the instant you lift off the brake. The point is to stop burning fuel while the car sits still.
The savings show up mostly in city driving, where idling time adds up. Most systems can be disabled with a button if you find the restarts intrusive, though the setting often resets each trip.
From the data: Of the 19,491 trims in the Trimslate dataset, 7,643 have a start-stop system.