For enhanced safety, the front and rear seat shoulder belts of the Audi A4 have pretensioners to tighten the seatbelts and eliminate dangerous slack in the event of a collision and force limiters to limit the pressure the belts will exert on the passengers. The Infiniti Q50 doesn’t offer pretensioners for its rear seat belts.
Both the A4 and Q50 have child safety locks to prevent children from opening the rear doors. The A4 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 Q50’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 Audi A4 has standard driver and front passenger side knee airbags mounted low on the dashboard. These airbags helps prevent the driver and front passenger from sliding under their seatbelts or the main frontal airbags; this keeps them better positioned during a collision for maximum protection. Knee airbags also help keep the legs from striking the dashboard, preventing knee and leg injuries in the case of a serious frontal collision. The Q50 doesn’t offer knee airbags.
The A4 has a standard Audi Backguard System, which use a specially designed headrest to protect the driver and front passenger from whiplash. During a rear-end collision, the Audi Backguard System moves the headrests forward to prevent neck and spine injuries. At the same time the pretensioning seatbelts fire, removing slack from the belts. The Q50 doesn’t offer a whiplash protection system.
The A4 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 Q50 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 A4. But it costs extra on the Q50.
Both the A4 and the Q50 have standard driver and passenger frontal airbags, front side-impact airbags, side-impact head airbags, 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, rearview cameras, available blind spot warning systems, around view monitors and rear cross-path warning.
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 available headlight’s “Good” rating, the Insurance Institute for Highway Safety grants the A4 the rating of “Top Safety Pick” for 2022, a rating granted to only 174 vehicles tested by the IIHS. The Q50 does not qualify as a “Top Safety Pick.”