For enhanced safety, the front and middle seat shoulder belts of the Toyota Sienna 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 Mercedes Metris Passenger doesn’t offer height-adjustable middle 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 Sienna are reminded to check the back seat if they opened the rear door before starting out. The Metris Passenger doesn’t offer a back seat reminder.
The Toyota Sienna has a standard driver’s side knee airbag mounted low on the dashboard. The knee airbag helps prevent the driver from sliding under the seatbelts or the main frontal airbag; this keeps the driver better positioned during a collision for maximum protection. A knee airbag also helps keep the legs from striking the dashboard, preventing knee and leg injuries in the case of a serious frontal collision. The Metris Passenger doesn’t offer knee airbags.
The Sienna 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 Metris Passenger 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 Sienna XLE/XSE/Woodland/Limited/Platinum has a standard Parking Support Brake that use rear sensors to monitor and automatically apply the brakes to prevent a rear collision. The Metris Passenger doesn’t offer backup collision prevention brakes.
The Sienna offers all-wheel drive to maximize traction under poor conditions, especially in ice and snow. The Metris Passenger doesn’t offer all-wheel drive.
The Sienna’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 Metris Passenger.
The Sienna Platinum has a standard Bird’s Eye View Monitor to allow the driver to see objects all around the vehicle on a screen. The Metris Passenger only offers a rear monitor and front and rear parking sensors that beep or flash a light. That doesn’t help with obstacles to the sides.
The Sienna 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. A system to reveal vehicles in the Metris Passenger’s blind spot costs extra.
To help make backing out of a parking space safer, the Sienna’s standard cross-path warning system uses sensors in the rear bumper to alert the driver to vehicles approaching from the side, helping the driver avoid collisions. The Metris Passenger doesn’t offer a cross-path warning system.
Both the Sienna and the Metris Passenger have standard driver and passenger frontal airbags, front side-impact airbags, side-impact head airbags, front seatbelt pretensioners, height adjustable front shoulder belts, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, collision warning systems, daytime running lights, 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 “Good” rating, the Insurance Institute for Highway Safety grants the Sienna its highest rating: “Top Pick Plus” for 2021, a rating granted to only 68 vehicles tested by the IIHS. The Metris Passenger has not been tested, yet.