Both the Discovery and Cayenne have child safety locks to prevent children from opening the rear doors. The Discovery 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 Cayenne’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 Discovery’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 Cayenne doesn’t offer a driver alert monitor.
Both the Discovery and the Cayenne have standard driver and passenger frontal airbags, front side-impact airbags, side-impact head airbags, four-wheel antilock brakes, all wheel drive, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, lane departure warning systems, blind spot warning systems, rearview cameras and rear cross-path warning.

