What happens when you press the ‘start-stop’ button in a moving car [Video]

Modern cars have become a lot more sophisticated, and are laden with gizmos. Features like keyless entry and start/stop button are now quite common in cars. There is much curiosity surrounding the keyless start/stop button, and many of you may have wondered about what will happen if the start/stop button is pressed while the car is still in motion. We did an experiment to see what really really happens when the start-stop button is pressed in a moving car.

So what happens?

We tried the experiment of pushing the start/stop button with the Toyota Yaris and expectedly, nothing happened. The driver console of the Yaris displayed a message saying “push and hold the button for an emergency stop” with three warning beeps. There is an internal safety mechanism built into such cars that protect the occupants from accidental touch to the button.

If there is an emergency and the car has to be stopped for any reason, pressing the button and holding it for a few seconds shuts down the engine. Now, this is only for emergency situations where the accelerator is stuck or something has happened that needs the car engine to be stopped immediately. However, all modern cars get electric or hydraulic power-steering. Stopping the engine causes the steering to become heavy.

Even the brakes of modern cars are engine assisted and stopping the engine causes them to lose their efficiency. It is extremely important that one uses extreme caution while stopping a vehicle when it is still in motion. The safety feature of keeping the button pressed for a few seconds to turn it off is to ensure that if someone accidentally touches it in motion, the car does not lose the capability to steer and brake properly.

It is important to know that the Toyota Yaris behaved in this way and other cars may be programmed to respond in other ways during such situations. Always make sure that your vehicle is in neutral or the clutch lever is pressed if it is a manual car, while turning off the vehicle in motion. Cutting the ignition suddenly will stop fuel supply to the engine, and the force from the moving vehicle can damage the engine!

Shantonil Nag

Shantonil brings a refined blend of expertise and enthusiasm to motoring journalism at With a career spanning over 11 years, he anchors Cartoq's insightful car reviews and test drives. His journalistic journey began as a correspondent at, where he honed his skills in content writing and scripting car reviews. Later, as Senior Editor for, his expanded role included curating and structuring web content. At, his expanded role includes assisting the video team to create high-quality car reviews. (Full bio)