Both the CT4 and A-Class have child safety locks to prevent children from opening the rear doors. The CT4 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 A-Class’ 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.
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 CT4 are reminded to check the back seat if they opened the rear door before starting out. The A-Class doesn’t offer a back seat reminder.
Over 200 people are killed each year when backed over by motor vehicles. The CT4 Premium Luxury/Sport has standard Reverse Automatic Braking that uses rear sensors to monitor for objects to the rear and automatically applies the brakes to prevent a collision. The A-Class doesn’t offer backup collision prevention brakes.
The CT4’s standard 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. A lane departure warning system costs extra on the A-Class.
To help make backing out of a parking space safer, the CT4’s standard Rear Cross Traffic Alert uses sensors in the rear to alert the driver to vehicles approaching from the side, helping the driver avoid collisions. The A-Class doesn’t offer a rear cross-path warning system.
Both the CT4 and the A-Class have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, blind spot warning systems, rearview cameras, available all wheel drive and around view monitors.