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 electronic stability system. Active head restraints for the front seats are designed to prevent whiplash injuries. In the convertible, active roll bars hide under the rear deck to maximize visibility. If the car senses a sideways tip, the bars raise to provide rollover protection.

Optional safety features include blind spot and lane departure warning systems and night vision with pedestrian detection.

A backup camera is standard, and buyers can choose additional top- and side-view cameras for added protection when parking and creeping into intersections.