For enhanced safety, the front and rear seat shoulder belts of the Mercedes C-Class Cabriolet 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 MINI Cooper Convertible doesn’t offer pretensioners for its rear seat belts.
The C-Class Cabriolet’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The Cooper Convertible doesn’t offer pre-crash pretensioners.
The C-Class Cabriolet has standard front and rear seat side-impact airbags and head airbags, which act as a forgiving barrier between the passengers and the door. Combined with high-strength steel door beams this system increases protection from broadside collisions. The Cooper Convertible doesn't offer rear-seat side-impact airbags, only ones for front seat occupants.
The C-Class Cabriolet offers all-wheel drive to maximize traction under poor conditions, especially in ice and snow. The Cooper Convertible doesn’t offer all-wheel drive.
The C-Class Cabriolet offers an optional Surround View System to allow the driver to see objects all around the vehicle on a screen. The Cooper Convertible 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 C-Class Cabriolet’s blind spot warning system uses sensors to alert the driver to objects in the vehicle’s blind spots where the side view mirrors don’t reveal them. The Cooper Convertible doesn’t offer a system to reveal objects in the driver’s blind spots.
To help make backing out of a parking space safer, the C-Class Cabriolet’s optional rear cross-path warning system uses sensors in the rear bumper to alert the driver to vehicles approaching from the side, helping the driver avoid collisions. The Cooper Convertible doesn’t offer a cross-path warning system.
Both the C-Class Cabriolet and the Cooper Convertible 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 and available lane departure warning systems.
The Mercedes C-Class Cabriolet weighs 736 to 1087 pounds more than the MINI Cooper Convertible. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts. Crosswinds also affect lighter cars more.