For enhanced safety, the front and rear seat shoulder belts of the Subaru Legacy 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 BMW 4 Series Gran Coupe doesn’t offer pretensioners for the rear seat belts.
For enhanced safety, the front seat shoulder belts of the Subaru Legacy are height-adjustable to accommodate a wide variety of driver and passenger heights. A better fit can prevent injuries and the increased comfort also encourages passengers to buckle up. The BMW 4 Series Gran Coupe doesn’t offer height-adjustable 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 Legacy are reminded to check the back seat if they opened the rear door before starting out. The 4 Series Gran Coupe doesn’t offer a back seat reminder.
Over 200 people are killed each year when backed over by motor vehicles. The Legacy Sport/Limited/Touring has standard Reverse Automatic Braking that uses rear sensors to monitor and automatically apply the brakes to prevent a rear collision. The 4 Series Gran Coupe doesn’t offer backup collision prevention brakes.
To provide maximum traction and stability on all roads, All-Wheel Drive is standard on the Legacy. But it costs extra on the 4 Series Gran Coupe.
The Legacy’s optional 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 4 Series Gran Coupe doesn’t offer a driver alert monitor.
Both the Legacy and the 4 Series Gran Coupe have standard driver and passenger frontal airbags, front side-impact airbags, driver knee airbags, side-impact head airbags, 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 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 standard headlight’s “Good” rating, the Insurance Institute for Highway Safety grants the Legacy its highest rating: “Top Pick Plus” for 2021, a rating granted to only 62 vehicles tested by the IIHS. The 4 Series Gran Coupe has not been tested, yet.