The brake pedal is down, the truck’s rear end is getting bigger, and your car’s nose is low enough to disappear beneath it. Volkswagen wants the car to grow a cage over its hood before that happens.
Telescoping rods would extend from the roof and hood to put a barrier between the passenger compartment and the truck, according to a patent filing discovered by Carmoses. Think of a roof rack that reaches forward and meets a pair of rising posts above the nose. Its job is deadly serious: keep the truck’s loading platform away from the windshield and the people behind it.
A Roof Rack With A Rescue Job
The nightmare here is called underride. A car slides beneath a taller vehicle, letting the truck’s rear edge bypass the structures designed to absorb a frontal crash. Instead of crushing the nose progressively, the collision can reach the windshield pillars and cabin.
VW’s cage changes the shape of the car just before impact. In everyday driving, its telescoping members stay retracted along the roof and in the hood area. When deployed, the roof-level members reach forward over the windshield and hood, while the front structure rises to meet them. Together they form a cage ahead of the occupants.
That elevated frame gives the truck something to hit before its rear edge reaches the cabin. A conventional roll cage surrounds the people inside a car; this one reaches out in front of them.
The driver would have no extra button to press. Radar and cameras feed a controller that predicts an unavoidable underride collision and triggers the protection. VW also allows for information from sensors on the truck or beside the road, with vehicles exchanging data directly or through roadside infrastructure.
That networking has roots in ordinary Volkswagens. The eighth-generation Golf arrived in 2019 with standard Car2X hazard communication, sharing warnings with equipped vehicles and receiving information from infrastructure. VW’s new proposal takes that conversation toward deciding how to prepare for an impact.
Give The Bumper An Airbag
A second approach tackles the height mismatch with a giant cushion. An airbag stored in the front bumper would inflate forward and upward, making the nose tall enough to meet the truck instead of slipping underneath.
This is much more than a padded bumper. The inflated bag needs to reach above the dangerous opening beneath the truck’s loading platform. VW proposes feeding it from a compressed-air source, such as a pressure bottle or compressor.
The same thinking works from the other end. A bag tucked beneath the truck’s rear loading surface would inflate into the space below it, filling the opening that the following car might otherwise enter. The truck effectively gains a cushioned lower edge, closing that gap before the car arrives.
Audi was already exploring external airbags and changes in vehicle height to tackle underride back in 2015. VW’s roof-and-hood cage adds a particularly striking mechanical answer to that long-running problem.
Make The Car Stand Taller
VW has other ways to bring the crash structures into alignment. Air suspension could raise the front of the car, or lift both axles, so the nose meets the truck at a more useful height. The taller vehicle could also lower itself to close the gap.
Even the brakes get a role. Hard braking tends to pitch a car nose-down, exactly the wrong direction when a truck’s rear platform is ahead. VW proposes shifting more braking effort toward the rear axle shortly before impact to reduce or reverse that dive.
Then comes the wildest option: a downward-directed explosive pressure pulse that gives the car an upward shove. The purpose is a rapid change in height, helping the front crash structure engage.
The Gap Is The Enemy
There is already a simpler defence hanging from many trailers: a rear underride guard. Strong ones matter enormously. IIHS tests guards with a midsize car travelling at 35 mph, including impacts where only 30 percent of the car’s width overlaps the trailer. Catching the corner is a much tougher assignment than hitting the middle.
That is why this problem deserves more imagination than another dashboard warning. Picture the cage on a future Golf-sized hatchback: a familiar, sensible family car carrying one very unusual last line of defence.
Carmakers patent far more than they build, but this is the sort of ungainly hardware worth finding room for.
