1. Skidding Airbags
The Mercedes-Benz Braking Bag recognizes that the limit to a car's ability to brake in an emergency is the available friction of the scant few square inches of tire contact patch at each corner of the car. What if more area could be available to slow the car in case of an emergency?
That's the thinking behind the Braking Bag. If the car's on-board computer concludes a collision is imminent, it will fire an airbag located under the front axle that will press a high-friction surface against the ground. This anchor will slow the car at a rate of more than 20 meters per second, the equivalent of more than 2 Gs of stopping force. Modern cars brake with a maximum of roughly 1 G of deceleration.
At a time when there is concern that a move to smaller cars will come at a price in safety, Mercedes estimates that this ability to scrub off speed before impact provides the same benefit as adding seven inches of length to the crush space at the front of the car.
An additional benefit is that the airbag lifts the front of the car by nearly three inches, offsetting the nose dive that occurs during emergency braking. This keeps the car's impact-absorbing crush zones in alignment with those on the other vehicle.
2. Expandable Door Beams
Another part of the car that Mercedes engineers imagine inflating is, improbably, the steel side-impact protection bars in the doors of our cars. To do this, they have come up with an inflatable metal structure that mounts inside the door like a regular side-impact beam, but one that it is made of corrugated steel. On impact, a high-pressure inflator pops the beam out to its full size.
With this beam, thin doors can provide the crush space of thick ones. Plus, the company says the inflatable beams are about a pound lighter than conventional ones. Mercedes does note that the high cost of the high-pressure inflation device means this is a technology that will not appear in production soon. Another challenge is that because deployment of this system dents the door skin, the company wants to develop software that is smart enough to precisely detect imminent side impacts without any chance of false alarms disfiguring the sheetmetal.
3. Inflating Seatbelts
Inflation is also on the minds of Ford engineers, who have developed a seatbelt that releases a mini airbag during a crash. In case of a crash, these belts expand in just 40 milliseconds. Since they're much smaller, in terms of volume, than a regular airbag and use just a small canister for gas--similar to a CO2 cartridge--the belts don't get hot like airbags do. The swelling seat belt will help keep smaller occupants in position for maximum protection during a crash, and they also spread the crash forces over five times as much body area compared to the narrow strip of a conventional belt.
Ford will debut this technology in the outboard second-row seats of the next-generation Explorer SUV, due later this year. The belts will be optional, but Ford says they'll cost less than the $395 Sync voice-control technology.
4. Autonomous Brakes
Mitigating the force of impact is good, but preventing the crash is always better. Volvo aims to keep cars--and pedestrians--intact with the first car that gives its onboard computer authority to apply full braking power.
The 2011 Volvo S60's Collision Warning system with Full Auto Brake and Pedestrian Safety uses a forward-looking camera and a radar sensor with a wider field of view than that used by previous systems. This lets the computer spot pedestrians moving from the side of the road into the car's path so it can take action to avoid hitting them if the driver does not. The system alerts the driver to brake when it detects a probable collision, and if the driver does not act, the car stops by itself.
5. Auto Steering Correction
While Volvo is working on autonomous braking, Toyota--in the 2010 Prius, Lexus HS250h and Lexus RX450h--can steer for the driver. When the active cruise control system is switched on, Toyota's Lane Keep Assist system engages to help prevent the car from drifting out of its lane.
The system watches the road ahead with a camera, and if it sees that the car is headed out of its lane--and the turn signal isn't indicating that this is intentional--it gently steers the car back into its lane.
The intention here is not to drive for the driver, but to reduce the need for constant corrective steering input that can fatigue the driver. Left entirely to its own devices, which is not the designers' intent, Lane Keep Assist will eventually pinball from one side of the lane to another until the needed corrective input exceeds the system's capability and it drifts across the lane divider.
Some other systems attempt to provide some of the same benefit by selectively braking one wheel to tug the car back into the middle of its lane, but Toyota's is the first that actually turns the steering wheel.