For enhanced safety, the front and rear seat shoulder belts of the Mercedes C-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 the rear seat belts.
For enhanced safety, the front and rear seat shoulder belts of the Mercedes C-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 C-Class Sedan’s driver alert monitor detects an inattentive driver then sounds a warning and suggests a break. According to the NHTSA, drivers who fall asleep cause about 100,000 crashes and 1500 deaths a year. The 3 Series Sedan doesn’t offer a driver alert monitor.
Both the C-Class Sedan and the 3 Series Sedan have standard driver and passenger frontal airbags, front side-impact airbags, head airbags, plastic fuel tanks, four wheel antilock brakes, traction control and electronic stability systems to prevent skidding.
For its top level performance in frontal, side, rear impact and roof-crush tests, the Insurance Institute for Highway Safety rates the C-Class Sedan as a “Top Pick” for 2012, a rating only granted to 120 vehicles tested by the IIHS. The 3 Series Sedan has not been tested, yet.
J.D. Power and Associates’ 2011 Initial Quality Study of new car owners surveyed provide the statistics that show that Mercedes vehicles are better in initial quality than BMW vehicles. J.D. Power ranks Mercedes fourth in initial quality, above the industry average. With 15 more problems per 100 vehicles, BMW is ranked 13th, below the industry average.
J.D. Power and Associates’ 2011 survey of the owners of three-year-old vehicles provides the long-term dependability statistics that show that Mercedes vehicles are more reliable than BMW vehicles. J.D. Power ranks Mercedes 8th in reliability, above the industry average. With 36 more problems per 100 vehicles, BMW is ranked 21st.
The C-Class Sedan has 1.6 gallons more fuel capacity than the 3 Series Sedan (17.4 vs. 15.8 gallons), for longer range between fill-ups.
The C-Class Sedan Luxury’s standard tires provide better handling because they have a lower 45 series profile (height to width ratio) that provides a stiffer sidewall than the 3 Series Sedan’s standard 50 series tires.
For better maneuverability, the C-Class Sedan’s turning circle is 1.8 feet tighter than the 3 Series Sedan’s (35.3 feet vs. 37.1 feet).
The design of the Mercedes C-Class Sedan amounts to more than styling. The C-Class Sedan has an aerodynamic coefficient of drag of .27 Cd. That is lower than the 3 Series Sedan (.29 to .3) and many sports cars. A more efficient exterior helps keep the interior quieter and helps the C-Class Sedan get better fuel mileage.
Unlike the driver-only memory system optional in the 3 Series Sedan, the C-Class Sedan offers an optional driver and passenger memory, so that when drivers switch, the memory setting adjusts the driver’s seat, steering wheel position and outside mirror angle and the front passenger seat also adjusts to the new passenger’s preset preferences.
To shield the driver and front passenger’s vision over a larger portion of the windshield and side windows, the C-Class Sedan has standard extendable sun visors. The 3 Series Sedan doesn’t offer extendable visors.