For enhanced safety, the front and second-row seat shoulder belts of the Mercedes GLB 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.
For enhanced safety, the front seat shoulder belts of the Mercedes GLB 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 X4 doesn’t offer height-adjustable seat belts.
Both the GLB and X4 have rear cross-traffic warning, but the GLB has Active Brake Assist (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 GLB and the X4 have standard driver and passenger frontal airbags, front side-impact airbags, driver knee airbags, side-impact head airbags, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, blind spot warning systems, rearview cameras, rear cross-path warning, driver alert monitors, available all wheel drive, lane departure warning systems and around view monitors.

