Both the G-Class and GX have Rear Cross-Traffic Alert, but the G-Class has Active Brake Assist (automatically applies the brakes) to better prevent a collision when backing near traffic. The GX’s Rear Cross-Traffic Alert doesn’t automatically brake.
Both the G-Class and the GX have standard driver and passenger frontal airbags, front and rear side-impact airbags, driver and front passenger knee airbags, side-impact head airbags, front and rear seatbelt pretensioners, height adjustable front shoulder belts, 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.

