For enhanced safety, the front and second-row seat shoulder belts of the Land Rover Defender have pretensioners to tighten the seatbelts and eliminate dangerous slack in the event of a collision and force limiters to limit the pressure the belts will exert on the passengers. The BMW X4 doesn’t offer pretensioners for its rear seat belts.
Both the Defender 110/130 and X4 have child safety locks to prevent children from opening the rear doors. The Defender 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 X4’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 Land Rover Defender’s rear backup camera has a standard washer for maintaining a clear view under various conditions. In contrast, the BMW X4 does not offer a rear camera washer, meaning its effectiveness relies on manual cleaning by the user when necessary.
Both the Defender and X4 have rear cross-traffic warning, but the Defender has Rear Traffic Braking (automatically applies the brakes) to better prevent a collision when backing near traffic. The X4’s Cross Traffic Warning doesn’t automatically brake.
Both the Defender and the X4 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, rear cross-path warning and driver alert monitors.
The Land Rover Defender weighs 427 to 1707 pounds more than the BMW X4. The NHTSA advises that heavier vehicles are much safer in collisions than their significantly lighter counterparts.

