For enhanced safety, the front and rear seat shoulder belts of the Mercedes E-Class Sedan 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 its rear seat belts.
For enhanced safety, the front seat shoulder belts of the Mercedes E-Class Sedan 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 3 Series Sedan doesn’t offer height-adjustable seat belts.
The E-Class Sedan has a standard front seat center airbag, which deploys between the driver and front passenger, protecting them from injuries caused by striking each other in serious side impacts. The 3 Series Sedan doesn’t offer front seat center airbags.
Earlier warning of stopped traffic, traffic signals, dangerous road conditions, weather, or accidents, can keep driver's safer and prevent crashes. The E-Class Sedan has Car-to-X Communication, a system that seamlessly communicates important warnings to the driver about impending danger, if they're available. The 3 Series Sedan doesn’t offer a system that can receive automated systems from infrastructure or other vehicles.
The E-Class Sedan has a standard blind spot warning system that 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 E-Class Sedan has standard Rear Cross-Traffic Alert and Active Brake Assist automatically engages the brakes to help avoid a collision. BMW charges extra for Cross Traffic Warning on the 3 Series Sedan and the 3 Series Sedan’s Cross Traffic Warning does not include automatic braking.
Both the E-Class Sedan and the 3 Series Sedan have standard driver and passenger frontal airbags, front side-impact airbags, driver 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.