The Volvo S90 offers optional built in child booster seats. They’re more crash worthy than an added child seat because of their direct attachment to the seat. Mercedes doesn’t offer the convenience and security of a built-in child booster seat in the CLS. Their owners must carry a heavy booster seat in and out of the vehicle; S90 owners can just fold their built-in child seat up or down.
The S90 has a standard Whiplash Protection System (WHIPS), which use a specially designed headrest to protect the driver and front passenger from whiplash. During a rear-end collision, the WHIPS moves the headrests forward to prevent neck and spine injuries. At the same time the pretensioning seatbelts fire, removing slack from the belts. The CLS doesn’t offer a whiplash protection system.
The S90 has standard Post-impact braking, which automatically apply the brakes in the event of a crash to help prevent secondary collisions and prevent further injuries. The CLS 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 S90 has standard CTA Auto Brake that uses rear sensors to monitor for objects to the rear and automatically applies the brakes to prevent a collision. The CLS doesn’t offer automatic braking for stationary objects directly to the rear.
To provide maximum traction and stability on all roads, All-Wheel Drive is standard on the S90. But it costs extra on the CLS.
The S90’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 CLS.
To help make backing out of a parking space safer, the S90 has standard rear cross-path warning, helping the driver avoid collisions. Mercedes charges extra for Rear Cross-Traffic Alert on the CLS.
Both the S90 and the CLS 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, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, blind spot warning systems, rearview cameras and driver alert monitors.
For its top level performance in IIHS driver and passenger-side small overlap frontal, moderate overlap frontal, side impact, roof strength and head restraint tests, its standard vehicle-to-vehicle front crash prevention system, its standard vehicle-to-pedestrian front crash prevention system, and its standard headlight’s “Acceptable” rating, the Insurance Institute for Highway Safety grants the S90 its highest rating: “Top Safety Pick Plus” for 2022, a rating granted to only 128 vehicles tested by the IIHS. The CLS has not been tested, yet.