For enhanced safety, the front and rear seat shoulder belts of the Kia K4 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 Audi S3 doesn’t offer pretensioners for its rear seat belts.
In the past twenty years hundreds of infants and young children have died after being left in vehicles, usually by accident. When turning the vehicle off, drivers of the K4 are reminded to check the back seat if they opened the rear door before starting out. The S3 doesn’t offer a back seat reminder.
Over 200 people are killed each year when backed over by motor vehicles. The K4 GT-Line Turbo offers optional Reverse Parking Collision-Avoidance Assist that uses rear sensors to monitor for objects to the rear and automatically applies the brakes to prevent a collision. The S3 doesn’t offer automatic braking for stationary objects directly to the rear.
The K4 GT-Line Turbo offers an optional Surround View Monitor to allow the driver to see objects all around the vehicle on a screen. The S3 only offers a rear monitor and front and rear parking sensors that beep or flash a light. That doesn’t help with obstacles to the sides.
The K4’s driver alert monitor detects an inattentive driver then sounds a warning and suggests a break. According to the NHTSA, drivers who fall asleep cause about 100,000 crashes and 1500 deaths a year. The S3 doesn’t offer a driver alert monitor.
Both the K4 and the S3 have standard driver and passenger frontal airbags, front and rear 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, rearview cameras, available blind spot warning systems and rear cross-path warning.