The X4’s pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The UX doesn’t offer pre-crash pretensioners.
To provide maximum traction and stability on all roads, All-Wheel Drive is standard on the X4. But it costs extra on the UX.
The X4 offers an optional Surround View to allow the driver to see objects all around the vehicle on a screen. The UX only offers a rear monitor and front and rear parking sensors that beep or flash a light. That doesn’t help with obstacles to the sides.
Both the X4 and the UX have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front seatbelt pretensioners, plastic fuel tanks, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, post-collision automatic braking systems, daytime running lights, lane departure warning systems, blind spot warning systems, rearview cameras, rear cross-path warning and driver alert monitors.
The BMW X4 weighs 603 to 948 pounds more than the Lexus UX. The NHTSA advises that heavier vehicles are much safer in collisions than their significantly lighter counterparts.

