Mercedes-Benz's ESF2009 Experimental Safety Vehicle showcases safety systems of the future
By Loz Blain
June 18, 2009
When Mercedes-Benz produced its last safety demonstrator car back in 1974, it showcased exotic new technology like airbags, head restraints and seatbelt tensioners - things which have become almost ubiquitous on new cars 30 years down the track. So it's worth taking a good look at some of the wild and crazy innovations on Benz's ESF2009 Experimental Safety Vehicle if you want to see where Mercedes thinks road safety is going in the next few decades. How about high-beam multi-zone headlights that intelligently dip only the LEDs shining directly at oncoming cars? Or inflatable metal structures that pop up for extra strength in a crash? What about a huge inflatable braking airbag that pops out under the car to provide a massive high-traction contact patch and doubles your braking power in an imminent crash? Amazing stuff, and there's more.
Mercedes-Benz's ESF2009 Experimental Safety Vehicle is the firm's latest concept car, and one focused entirely on road safety. The list of brand new innovations on this beast is quite astounding - quite the tonic if you think you've seen it all before. Here goes.
When the car's sensors detect an unavoidable, imminent collision, the braking bag is deployed. It's a huge airbag with a high-friction coating that pops out between the axles of the car, and acts as a massive braking contact patch to produce a huge decelerative force that tires alone can't match.
The total deceleration power of a high performance sports car is about 1G - the braking bag would more than double that stopping power as it lifts the wheels up to 8cm off the ground. Theoretically, at 2G deceleration, you could come to a dead stop from 72kmh in one second - then, presumably, spend the next five minutes groping around trying to find your eyeballs.
Because you're riding on an air cushion when you hit whatever is in front of you, the braking bag also acts like an extra crumple zone, dissipating some crash energy. It's also set up to substantially reduce braking dive so that if you're hitting another vehicle, the nose isn't down; the car is optimally positioned for impact.
PRE-SAFE inflatable metal structures
Still in its infancy, this one's all about metal shields that stay folded away during normal driving, but shoot out and provide greatly improved strength in the event of a crash. The PRE-SAFE inflatable structures can either be activated according to imminent collision information from the collision detection systems or, in the case of shields mounted further inside the car, around the seats and inner cross-members, they can be triggered by the crash itself.
The inflatable structures in the ESF2009 don't yet have the ability to retract - so the pre-collision sensors had better be pretty accurate.
Partial Main Beam intelligent headlights and spotlights
When you're attacking a dark country highway at night, there's a few moments of real vulnerability as you dip your headlights and try to stay on your side of the road, while being blinded by oncoming traffic. Mercedes is trying to do away with these moments using its clever Partial Main Beam system.
The headlamps are made up of 100 individually controlled LEDs. An infrared camera recognizes oncoming traffic when you've got your brights on, and then dims only the LEDs that are reflected directly at that vehicle. The result is that, while you're not blinding the oncoming driver, the rest of the road is fully illuminated.
The partial main beam sensor also works as a kind of spotlight when you're using your low-beam lights around town; if the infrared cameras detect, for example, a pedestrian or animal in front of you, the Partial Main Beam system can spotlight that potential hazard in bright light, calling your attention to it, as well as alerting the pedestrian to your presence. Very smart.
Interactive vehicle communication
Mercedes believes what one car's collision detection systems report should be of use to all other road users too - so if your systems pick up a hazard, it's broadcast so that other cars with similar systems can pick it up well in advance.
The initial system broadcasts more than 500 meters, but Benz expects that roadside broadcast stations and oncoming traffic will re-broadcast the signal significantly further. It's amusing to note that the system is designed to pick up police cars and highlight them as a hazard - not a bad idea.
The vehicle communication system is being tested using up to 400 vehicles from Mercedes-Benz and other German manufacturers. Testing started in 2008 and will continue until 2012. The company predicts that a full coverage network of real-time mobile information will become available when about 10 percent of cars carry the system.
PRE-SAFE Pulse - moving passengers to safety during a collision
When crumple zones, airbags, side-impact intrusion protection and other systems kick in to protect a car's occupants in a crash, millimeters can make all the difference between injury and fatality.
The idea of the PRE-SAFE Pulse system is to fire air chambers in the seats during a collision, pushing the occupants in towards the safer center of the car, with a firm nudge in the ribs. The force of this nudge is determined by things like lateral acceleration, steering angle and speed - and the system is designed to put you up to 50mm further away from the impact when it hits.
Mercedes clearly believes that kids mucking about in the back seat - and drivers turning around to see what they're up to and give them a mouthful for it - are a significant road safety issue.
So they've mounted a Child Cam in the roof area that can display still photos - not video, that would be distracting - of what the kids are up to in the back on the LCD dash screen. So you've genuinely got eyes in the back of your head to work out who's pulling whose hair or who has wriggled out of their seatbelt.
When there's more than one person in a car, the other occupants can become a serious safety risk in a crash - take a side impact, in which the back seat passengers might well be restrained by seatbelts. The passenger often sees the impact coming and tries to move away from it - and this motion, combined with the impact, can cause passengers to knock their heads together in a devastating accidental headbutt.
Mercedes attempts to solve this issue in the ESF2009 with an inter-seat airbag system that inflates soft barriers between passengers as the crash happens, isolating each person from the rest and cushioning the movement of all bodies in the car post-impact.
The Belt-Bag inflating seatbelt
Seatbelts have already saved countless lives, and they remain the primary source of protection in collisions, particularly to backseat passengers who don't often get an airbag.
The ESF2009's Belt-Bag innovation is one of the ones most likely to make it to a production Benz in the near future. As the name suggests, it's an inflatable seatbelt that's triggered in a collision.
The Belt-Bag unfolds as it inflates, almost doubling its surface contact with the wearer to distribute its restraining force across a wider section of the body, as well as contributing an air cushioning effect. Very nifty.
Size-adaptive front airbags
It makes sense if you think about it - a tall passenger with the seat right back is going to need a bigger airbag than a small one whose head is much closer to the dash. So the safety gurus at Mercedes have incorporated a system that adjusts both the timing and the amount of air injected into the airbag depending on who's sitting in it.
The system takes weight, seat position and other information into account to determine how big the airbag needs to be; a standard airbag inflates to about 120 liters, but the ESF2009's adaptive airbags can go between 90 and 150 liters, controlled by automatically adjusting retainer bands.
The PRE-SAFE demonstrator
This is all pretty nifty technology - but in an ideal world, none of us would ever get to see it in action. That's why Mercedes has put together a demonstrator vehicle which will be trollied out at major auto shows, starting at this year's ESV conference in Stuttgart.
Passengers can sit in the cabin, a cut-down version of an S-Class saloon, which is accelerated on a linear drive to about 16kmh, and then crashed into a hydraulic shock absorber to demonstrate the safety systems inside. It can be crashed at any angle up to 30 degrees, and can also simulate rear-end collisions or be set sideways to demonstrate the effect of high-G cornering.
With road trauma fatalities reaching more than a million deaths a year worldwide, it's great to see Mercedes taking a leading role in developing and publicizing these sorts of safety systems. There's some great ideas in this concept vehicle, and we'd love to see them on the road before too long.