In the past twenty years hundreds of infants and young children have died after being left in vehicles, usually by accident. When turning the vehicle off, drivers of the Sonata are reminded to check the back seat if they opened the rear door before starting out. The C-Class Sedan doesn’t offer a back seat reminder.
The Sonata’s lane departure warning system alerts a temporarily inattentive driver when the vehicle begins to leave its lane and gently nudges the vehicle back towards its lane. The C-Class Sedan doesn’t offer a lane departure warning system.
To help make backing out of a parking space safer, the Sonata has standard Rear Cross-Traffic Collision Warning and Rear Cross-Traffic Collision-Avoidance Assist automatically engages the brakes to help avoid a collision. Mercedes charges extra for Rear Cross-Traffic Alert on the C-Class Sedan.
Both the Sonata and the C-Class Sedan have standard driver and passenger frontal airbags, front side-impact airbags, driver knee airbags, side-impact head airbags, front and rear seatbelt pretensioners, height adjustable front shoulder belts, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, blind spot warning systems, rearview cameras, driver alert monitors and available all wheel drive.

