Both the Cayenne and AMG GLB have child safety locks to prevent children from opening the rear doors. The Cayenne 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 AMG GLB’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.
The Porsche Cayenne 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 AMG GLB doesn’t offer a front passenger side knee airbag.
Over 200 people are killed each year when backed over by motor vehicles. The Cayenne has standard Maneuver Assist that uses rear sensors to monitor for objects to the rear and automatically applies the brakes to prevent a collision. The AMG GLB doesn’t offer automatic braking for stationary objects directly to the rear.
A passive infrared night vision system optional on the Cayenne 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 AMG GLB doesn’t offer a night vision system.
The Cayenne’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 AMG GLB.
Both the Cayenne and the AMG GLB have standard driver and passenger frontal airbags, front side-impact airbags, driver knee airbags, side-impact head airbags, front seatbelt pretensioners, height adjustable front shoulder belts, four-wheel antilock brakes, all wheel drive, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, blind spot warning systems, around view monitors, rear cross-path warning and driver alert monitors.
The Porsche Cayenne weighs 809 to 1795 pounds more than the Mercedes AMG GLB. The NHTSA advises that heavier vehicles are much safer in collisions than their significantly lighter counterparts.