Both the S60 and C-Class Sedan have child safety locks to prevent children from opening the rear doors. The S60 Plus/Ultimate has power child safety locks, allowing the driver to activate and deactivate them from the driver's seat and to know when they're engaged. The C-Class Sedan’s child locks have to be individually engaged at each rear door with a manual switch. The driver can’t know the status of the locks without opening the doors and checking them.
The S60 has a standard Whiplash Protection System (WHIPS), which use a specially designed seat to protect the driver and front passenger from whiplash. During a rear-end collision, the WHIPS allows the backrest to travel backwards to cushion the occupants and the headrests move forward to prevent neck and spine injuries. At the same time the pretensioning seatbelts fire, removing slack from the belts. The C-Class Sedan doesn’t offer a whiplash protection system.
The S60’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 S60 has standard Cross Traffic Alert and Braking Intervention automatically engages the brakes to help avoid a collision. Mercedes charges extra for Rear Cross-Traffic Alert on the C-Class Sedan.
Both the S60 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, post-collision automatic braking systems, daytime running lights, blind spot warning systems, rearview cameras, driver alert monitors, available all wheel drive and around view monitors.