The A6 Allroad’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The QX55 doesn’t offer pre-crash pretensioners.
Both the A6 Allroad and QX55 have child safety locks to prevent children from opening the rear doors. The A6 Allroad 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 QX55’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 Allroad 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 QX55 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.
A passive infrared night vision system optional on the A6 Allroad Prestige 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. The QX55 doesn’t offer a night vision system.
Both the A6 Allroad and the QX55 have standard driver and passenger frontal airbags, front and rear side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front and rear seatbelt pretensioners, height adjustable front shoulder belts, four-wheel antilock brakes, All-wheel drive, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, lane departure warning systems, rearview cameras, available blind spot warning systems and rear cross-path warning.
The Audi A6 Allroad weighs 420 to 471 pounds more than the Infiniti QX55. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts.
For its top level performance in IIHS driver and passenger-side small overlap frontal, moderate overlap frontal, side impact, roof strength and head restraint tests, its standard vehicle-to-vehicle front crash prevention system, its standard vehicle-to-pedestrian front crash prevention system, and its standard headlight’s “Good” rating, the Insurance Institute for Highway Safety grants the A6 Allroad its highest rating: “Top Pick Plus” for 2021, a rating granted to only 73 vehicles tested by the IIHS. The QX55 has not been tested, yet.