For enhanced safety, the front seat shoulder belts of the Lexus UX are height-adjustable to accommodate a wide variety of driver and passenger heights. A better fit can prevent injuries and the increased comfort also encourages passengers to buckle up. The BMW X3 doesn’t offer height-adjustable seat belts.
In the past twenty years hundreds of infants and young children have died after being left in vehicles, usually by accident. When turning the vehicle off, drivers of the UX are reminded to check the back seat if they opened the rear door before starting out. The X3 doesn’t offer a back seat reminder.
Using vehicle speed sensors and seat sensors, smart airbags in the UX deploy with different levels of force or don’t deploy at all to help better protect passengers of all sizes in different collisions. The UX’s side airbags will shut off if a child is leaning against the door. The X3’s side airbags don’t have smart features and will always deploy full force.
The UX has a standard Secondary Collision Brake, which automatically applies the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The X3 doesn’t offer a post collision braking system: in the event of a collision that triggers the airbags, more collisions are possible without the protection of airbags that may have already deployed.
Both the UX and X3 have rear cross-traffic warning, but the UX offers optional Parking Support Brake (automatically applies the brakes) to better prevent a collision when backing near traffic. The X3’s Cross Traffic Warning doesn’t automatically brake.
The UX’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 X3 doesn’t offer a driver alert monitor.
Both the UX and the X3 have standard driver and passenger frontal airbags, front side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front and rear seatbelt pretensioners, plastic fuel tanks, four-wheel antilock brakes, 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, available all wheel drive and rear parking sensors.