The GLS’ pre-crash front seatbelts will tighten automatically in the event the vehicle detects an impending crash, improving protection against injury significantly. The Highlander doesn’t offer pre-crash pretensioners.
To provide maximum traction and stability on all roads, All-Wheel Drive is standard on the GLS. But it costs extra on the Highlander.
The GLS has a standard blind spot warning system which uses sensors to alert the driver to objects in the vehicle’s blind spots where the side view mirrors don’t reveal them. Only the Highlander LE/XLE/XSE/Limited/Platinum offers a blind spot warning system.
To help make backing out of a parking space safer, the GLS has a standard rear cross-path warning system, which uses sensors in the rear bumper to alert the driver to vehicles approaching from the side, helping the driver avoid collisions. Only the Highlander LE/XLE/XSE/Limited/Platinum has a rear cross-path warning system.
Both the GLS and the Highlander have standard driver and passenger frontal airbags, front side-impact airbags, driver knee airbags, side-impact head airbags, front and rear seatbelt pretensioners, height adjustable front shoulder belts, plastic fuel tanks, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, rearview cameras, driver alert monitors and available lane departure warning systems.
The Mercedes GLS weighs 1014 to 1930 pounds more than the Toyota Highlander. The NHTSA advises that heavier vehicles are much safer in collisions than their significantly lighter counterparts.

