For enhanced safety, the front seat shoulder belts of the Ford Mustang Mach-E 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 i4 doesn’t offer height-adjustable seat belts.
Both the Mustang Mach-E and i4 have child safety locks to prevent children from opening the rear doors. The Mustang Mach-E 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 i4’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.
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 Mustang Mach-E are reminded to check the back seat if they opened the rear door before starting out. The i4 doesn’t offer a back seat reminder.
Both the Mustang Mach-E and i4 have rear cross-traffic warning, but the Mustang Mach-E has Cross Traffic Braking (automatically applies the brakes) to better prevent a collision when backing near traffic. The i4’s Cross Traffic Warning doesn’t automatically brake.
Both the Mustang Mach-E and the i4 have standard driver and passenger frontal airbags, front side-impact airbags, driver 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 and driver alert monitors.