For enhanced safety, the front and rear seat shoulder belts of the Audi RS 6 have pretensioners to tighten the seatbelts and eliminate dangerous slack in the event of a collision. The BMW M5 doesn’t offer pretensioners for its rear seat belts.
For enhanced safety, the front seat shoulder belts of the Audi RS 6 are height-adjustable to accommodate a wide variety of driver and passenger heights. A better fit can prevent injuries and the increased comfort also encourages passengers to buckle up. The BMW M5 doesn’t offer height-adjustable seat belts.
Both the RS 6 and M5 have child safety locks to prevent children from opening the rear doors. The RS 6 has power child safety locks, allowing the driver to activate and deactivate them from the driver's seat and to know when they're engaged. The M5’s child locks have to be individually engaged at each rear door with a manual switch. The driver can’t know the status of the locks without opening the doors and checking them.
A passive infrared night vision system optional on the RS 6 helps the driver to more easily detect people, animals or other objects in front of the vehicle at night. Using an infrared camera to detect heat, the system then displays the image on a monitor in the dashboard. The M5 doesn’t offer a night vision system.
Both the RS 6 and the M5 have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, four-wheel antilock brakes, all wheel drive, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, post-collision automatic braking systems, daytime running lights, lane departure warning systems, rearview cameras, available blind spot warning systems and rear cross-path warning.
The Audi RS 6 weighs 562 to 867 pounds more than the BMW M5. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts.