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 4 Series Gran Coupe are reminded to check the back seat if they opened the rear door before starting out. The IS doesn’t offer a back seat reminder.
The 4 Series Gran Coupe’s standard pretensioning seatbelts also sense rear collisions and remove slack from the front seatbelts to help protect the occupants from whiplash and other injuries. The IS doesn’t offer a whiplash protection system.
The 4 Series Gran 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 IS doesn’t offer a driver alert monitor.
Both the 4 Series Gran Coupe and the IS have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, 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, blind spot warning systems, rearview cameras, rear cross-path warning, available all wheel drive and around view monitors.

