More and more, we're hearing about vehicle navigation and communication/entertainment systems that are able to access the internet. As these systems begin to become standard in all new cars, the possibilities for using them to allow cars to communicate with one another will start to open up. Along those lines, Italy's University of Bologna has developed an app that should allow vehicles on a motorway to instantly notify one another when an accident occurs. In computer simulations, it has been shown to reduce multi-car pile-ups by approximately 40 percent.

The process would start with the vehicle(s) that was involved in the initial accident, in which an onboard acceleration sensor would detect the movements that are unique to being in an accident. The app in that car would then relay a warning signal to the vehicles behind it, which would in turn relay it to the vehicles behind them, and so on. Drivers would be warned of the accident ahead, and could take steps to avoid becoming part of it.

If every car that received the signal passed it on, however, maximum bandwidth would soon be reached, and communication would cease. Instead, while every vehicle within 300 to 1,000 meters (984 to 3,281 feet) would receive the signal, only one would be chosen to relay it. The most distant vehicle that was still in range would seem to be the obvious choice, as it could presumably send the signal the farthest back. In reality, however, that vehicle's ongoing signal could be blocked by a truck, it could have a weak transmitter, or might otherwise not be the best choice.

In order to choose the best vehicle for relaying the signal, cars using the app would constantly stay in contact, continually assessing one another's transmitting capacities, along with their speed and direction of travel. As soon as one of those cars got in an accident, it would instantly know which vehicle following it should relay its warning signal. That vehicle, in turn, would be able to tell which vehicle behind it should pass the message along. In the U Bologna simulations, the use of such a system halved the amount of time required for the warning to be transmitted.

Toyota is working on the hardware required for the system, which will be road tested in coming months, in and around Los Angeles' UCLA campus.