For enhanced safety, the front and rear seat shoulder belts of the Lexus UX 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 Fiat 500X doesn’t offer pretensioners for its rear 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 500X doesn’t offer a back seat reminder.
The Lexus UX 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 500X doesn’t offer a front passenger side knee airbag.
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 500X’s side airbags don’t have smart features and will always deploy full force.
The Insurance Institute for Highway Safety tests front crash prevention systems. With a score of 6 points, IIHS rates the Pre-Collision System in the UX as “Superior.” The 500X scores only 4 points and is rated only “Advanced.”
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 500X 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.
Over 200 people are killed each year when backed over by motor vehicles. The UX offers an optional Parking Support Brake that uses rear sensors to monitor for objects to the rear and automatically applies the brakes to prevent a collision. The 500X doesn’t offer backup collision prevention brakes.
The UX’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 500X and is only available on 500X Sport.
The UX has a standard blind spot warning system that uses sensors to alert the driver to objects in the vehicle’s blind spots where the side view mirrors don’t reveal them and moves the vehicle back into its lane. A system to reveal vehicles in the 500X’s blind spot costs extra.
To help make backing out of a parking space safer, the UX has standard Rear Cross-Traffic Alert, helping the driver avoid collisions. Fiat charges extra for Rear Cross Path Detection on the 500X, and only on the Sport.
Both the UX and the 500X have standard driver and passenger frontal airbags, front side-impact airbags, driver knee airbags, side-impact head airbags, height adjustable front shoulder belts, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, rearview cameras, available all wheel drive and rear parking sensors.
For its performance in IIHS driver-side and passenger-side small overlap frontal, moderate overlap frontal, updated side impact, headlight, daytime pedestrian crash prevention, and nighttime pedestrian crash prevention testing, the Insurance Institute for Highway Safety grants the UX its highest rating: “Top Safety Pick Plus” for 2023, a rating granted to only 29 vehicles tested by the IIHS. The 500X last would have qualified as only a standard “Top Safety Pick” in 2017.