The 911 has standard head airbag curtains which act as a forgiving barrier between the driver and front passenger's upper bodies and the window and pillars. Combined with high-strength steel door beams and lower side airbags this system increases head protection in broadside collisions. The Roma doesn't offer side airbag protection for the head.
The 911 (except GT3) has standard Warn and Brake Assist, which use forward mounted sensors to warn the driver of a possible collision ahead. If the driver doesn’t react and the system determines a collision is imminent, it automatically applies the brakes at full-force in order to reduce the force of the crash or avoid it altogether. The Roma doesn't offer collision warning or crash mitigation brakes.
Over 200 people are killed each year when backed over by motor vehicles. The 911 (except Manual/GT3) offers an optional Maneuvering Assist that uses rear sensors to monitor for objects to the rear and automatically applies the brakes to prevent a collision. The Roma doesn’t offer backup collision prevention brakes.
The 911 offers all-wheel drive to maximize traction under poor conditions, especially in ice and snow. The Roma doesn’t offer all-wheel drive.
A passive infrared night vision system optional on the 911 helps the driver to more easily detect people, animals or other objects in front of the vehicle at night. Using an infrared camera to detect heat, the system then displays the image on a monitor in the dashboard. The Roma doesn’t offer a night vision system.
The 911’s 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. The Roma doesn’t offer a lane departure warning system.
The 911 offers an optional Surround View to allow the driver to see objects all around the vehicle on a screen. The Roma only offers front and rear parking sensors that beep or flash a light. That doesn’t help with obstacles to the sides.
The 911’s optional blind spot warning system uses sensors to alert the driver to objects in the vehicle’s blind spots where the side view mirrors don’t reveal them. The Roma doesn’t offer a system to reveal objects in the driver’s blind spots.
To help make backing out of a parking space safer, the 911’s optional Rear Cross Traffic Alert uses sensors in the rear to alert the driver to vehicles approaching from the side and automatically engage the brakes. The Roma doesn’t offer a rear cross-path warning system.
The 911’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 Roma doesn’t offer a driver alert monitor.
Both the 911 and the Roma have standard driver and passenger frontal airbags, front side-impact airbags, front seatbelt pretensioners, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding and rear parking sensors.