See also:

Locking and unlocking
Pressing the buttons locks and unlocks the doors and the trunk lid when the front doors are closed, but they are not secured against theft. The fuel filler flap remains unlocked. ...

Safety
Both the coupe and convertible have front airbags plus side-impact airbags built into the front seats. As required of all 2012 models sold in the U.S., the 640i has standard antilock brakes and an ...

Convertible: rollover protection system
The rollover protection system is activated automatically in the event of an accident, a critical driving situation, an extreme tilt in the car's longitudinal axis or upon loss of ground conta ...