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 ES doesn’t offer pre-crash pretensioners.
Both the A6 and ES 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 ES’ 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.
To provide maximum traction and stability on all roads, All-Wheel Drive is standard on the A6. But it costs extra on the ES.
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 ES doesn’t offer a system that can receive automated systems from infrastructure.
To help make backing out of a parking space safer, the A6 has standard Rear Cross-Traffic Assist with Automatic Brake Activation, systems which detect vehicles approaching from the sides and can automatically apply the brakes to prevent a collision. Rear Cross-Traffic Braking costs extra on the ES.
Both the A6 and the ES have standard driver and passenger frontal airbags, front and rear 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, post-collision automatic braking systems, 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 573 to 620 pounds more than the Lexus ES. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts.

