The only time I’ve ever really seen it happen is on cars that have auto stop/start, which essentially turn themselves off anyway.
Edit: Thanks for the answers everyone! I, in fact, did not know to begin with that it is called the tachometer and measured the revolutions of the engine and not the tires!
In: 5
As other have said, the engine has to keep spinning when the car comes to a stop. Internal combustion engines have a minimum RPM that they need to maintain to run. Each explosion of fuel pushes the pistons and compresses the next bit of fuel to be ignited, kinda like dominos each cycle of the engine takes some energy from the one before it to keep the process going. If you slow down the engine too much you interrupt that cycle and the engine stalls and shuts off.
Your automatic transmission uses something called a torque converter to keep this from happening. It’s basically a chamber filled with fluid, and two “propellers.” One is attached to the engine and the other the wheels. The fluid lets the engine to push on the wheels, but allows them to spin at different speeds. A manual transmission requires the driver to disconnect the engine and wheels every time they push the clutch pedal. If you keep the car in gear and try and bring it to a stop with the brakes, at some point the engine will shudder and stall. The wheels are providing too much resistance for the engine to overcome.
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