Over 200 people are killed each year when backed over by motor vehicles. The 4 Series Coupe 440i offers an optional Active Park Distance Control that uses rear sensors to monitor for objects to the rear and automatically applies the brakes to prevent a collision. The S5 doesn’t offer backup collision prevention brakes.
The 4 Series Coupe has a standard blind spot warning system that uses sensors to alert the driver to objects in the vehicle’s blind spots where the side view mirrors don’t reveal them and moves the vehicle back into its lane. A system to reveal vehicles in the S5’s blind spot costs extra.
To help make backing out of a parking space safer, the 4 Series Coupe has standard Cross Traffic Warning, helping the driver avoid collisions. Audi charges extra for rear cross-path warning on the S5.
The 4 Series Coupe’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 S5 doesn’t offer a driver alert monitor.
Both the 4 Series Coupe and the S5 have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, 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 all wheel drive and around view monitors.