The M4’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The Mustang doesn’t offer pre-crash pretensioners.
The M4’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 Mustang doesn’t offer a whiplash protection system.
The M4 has a standard PostCrash iBrake, which automatically applies the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The Mustang doesn’t offer a post collision braking system: in the event of a collision that triggers the airbags, more collisions are possible without the protection of airbags that may have already deployed.
Over 200 people are killed each year when backed over by motor vehicles. The M4 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 Mustang doesn’t offer backup collision prevention brakes.
The M4 offers all-wheel drive to maximize traction under poor conditions, especially in ice and snow. The Mustang doesn’t offer all-wheel drive.
The M4 offers an optional Surround View to allow the driver to see objects all around the vehicle on a screen. The Mustang only offers a rear monitor and rear parking sensors that beep or flash a light. That doesn’t help with obstacles to the front or sides.
Both the M4 and the Mustang have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, lane departure warning systems, blind spot warning systems, rearview cameras, rear cross-path warning and driver alert monitors.

