The Ford Mustang has standard driver and front passenger side knee airbags mounted low on the dashboard. These airbags helps prevent the driver and front passenger from sliding under their seatbelts or the main frontal airbags; this keeps them better positioned during a collision for maximum protection. Knee airbags also help keep the legs from striking the dashboard, preventing knee and leg injuries in the case of a serious frontal collision. The WRX doesn’t offer a front passenger side knee airbag.
The Mustang has standard Post Collision Braking, which automatically apply the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The WRX 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.
The Mustang’s standard lane departure warning system alerts a temporarily inattentive driver when the vehicle begins to leave its lane and gently nudges the vehicle back towards its lane. A lane departure warning system costs extra on the WRX.
The Mustang 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. Only the WRX Limited/GT offers a blind spot warning system.
To help make backing out of a parking space safer, the Mustang has standard Cross Traffic Alert and Cross Traffic Braking automatically engages the brakes to help avoid a collision. Only the WRX Limited/GT offers Rear Cross Traffic Alert and the WRX’s Rear Cross Traffic Alert does not include automatic braking.
The Mustang’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 WRX doesn’t offer a driver alert monitor.
Both the Mustang and the WRX have standard driver and passenger frontal airbags, front side-impact airbags, driver knee airbags, side-impact head airbags, front and rear seatbelt pretensioners, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, daytime running lights and rearview cameras.