For enhanced safety, the front and rear seat shoulder belts of the Audi S4 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 Volkswagen Jetta GLI doesn’t offer pretensioners for its rear seat belts.
The S4’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The Jetta GLI doesn’t offer pre-crash pretensioners.
Both the S4 and Jetta GLI have child safety locks to prevent children from opening the rear doors. The S4 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 Jetta GLI’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 S4 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 Jetta GLI doesn’t offer knee airbags.
The S4 has all-wheel drive to maximize traction under poor conditions, especially in ice and snow. The Jetta GLI doesn’t offer all-wheel drive.
The S4 Premium Plus/Prestige has a standard Top View Cameras to allow the driver to see objects all around the vehicle on a screen. The Jetta GLI only offers a rear monitor.
Both the S4 and the Jetta GLI have standard driver and passenger frontal airbags, front side-impact airbags, side-impact head airbags, height adjustable front shoulder belts, plastic fuel tanks, 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, rearview cameras, available blind spot warning systems and rear cross-path warning.
The Audi S4 weighs 492 to 575 pounds more than the Volkswagen Jetta GLI. The NHTSA advises that heavier cars are much safer in collisions than their significantly lighter counterparts.
Instrumented handling tests conducted by the National Highway Traffic Safety Administration and analysis of its dimensions indicate that the S4, with its five-star roll-over rating, is 3.2% less likely to roll over than the Jetta GLI, which received a four-star rating.