The A6’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The CT5 doesn’t offer pre-crash pretensioners.
Both the A6 and CT5 have child safety locks to prevent children from opening the rear doors. The A6 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 CT5’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 A6 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 CT5 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 A6. But it costs extra on the CT5.
Earlier warning of stopped traffic, traffic signals, dangerous road conditions, weather, or accidents, can keep driver's safer and prevent crashes. The A6 has Car-to-X Services, a system that seamlessly communicates important warnings to the driver about impending danger, if they're available. The CT5 doesn’t offer a system that can receive automated systems from infrastructure.
Both the A6 and the CT5 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, lane departure warning systems, blind spot warning systems, rearview cameras, rear cross-path warning, driver alert monitors and available around view monitors.
The Audi A6 weighs 483 to 647 pounds more than the Cadillac CT5. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts.

