See also:

Start/Stop button
The concept Pressing the Start/Stop button switches the ignition on or off and starts the engine. The engine starts if the brake pedal is pressed when you press the Start/Stop button. ...

After the ignition is switched off
The roof can still be operated for approx. 1 minute, as long as no door has been opened. ...

Safety
The BMW 1 Series hasn't been crash-tested. It includes frontal, front-seat side-impact and side curtain airbags. Also standard are antilock brakes and an electronic stability system with traction ...