For enhanced safety, the front and rear seat shoulder belts of the Mercedes CLA have pretensioners to tighten the seatbelts and eliminate dangerous slack in the event of a collision and force limiters to limit the pressure the belts will exert on the passengers. The BMW 3 Series Sedan doesn’t offer pretensioners for the rear seat belts.
The CLA offers an optional Surround View System to allow the driver to see objects all around the vehicle on a screen. The 3 Series Sedan only offers a rear monitor and front and rear parking sensors that beep or flash a light. That doesn’t help with obstacles to the sides.
The CLA has a standard blind spot warning system which uses sensors to alert the driver to objects in the vehicle’s blind spots where the side view mirrors don’t reveal them. A system to reveal vehicles in the 3 Series Sedan’s blind spot costs extra.
To help make backing out of a parking space safer, the CLA has a standard rear cross-path warning system, which uses sensors in the rear bumper to alert the driver to vehicles approaching from the side, helping the driver avoid collisions. Rear cross-path warning costs extra on the 3 Series Sedan.
Both the CLA and the 3 Series Sedan 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, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, rearview cameras, driver alert monitors, available all wheel drive and lane departure warning systems.