The A8 has a standard front seat center airbag, which deploys between the driver and front passenger, protecting them from injuries caused by striking each other in serious side impacts. The CLS doesn’t offer front seat center airbags.
The A8 has a standard Secondary Collision Brake Assist, which automatically applies the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The CLS doesn’t offer a post collision braking system: in the event of a collision that triggers the airbags, more collisions are possible without the protection of airbags that may have already deployed.
To provide maximum traction and stability on all roads, All-Wheel Drive is standard on the A8. But it costs extra on the CLS.
A passive infrared night vision system optional on the A8 helps the driver to more easily detect people, animals or other objects in front of the vehicle at night. Using an infrared camera to detect heat, the system then displays the image on a monitor in the dashboard and even aims one of the vehicle’s headlights in the direction of the person or object. The CLS doesn’t offer a night vision system.
The A8’s standard lane departure warning system alerts a temporarily inattentive driver when the vehicle begins to leave its lane. A lane departure warning system costs extra on the CLS.
Both the A8 and the CLS have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front 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, rearview cameras, available blind spot warning systems and rear cross-path warning.
The Audi A8 weighs 518 pounds more than the Mercedes CLS. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts.