A second level of communication involves more detail -- the car could send out its current path prediction according to GPS routing, for example, or warn the driver about unsafe traffic conditions reported from other vehicles. One early sign of this was Dash Navigation's Dash Express GPS system, which debuted in early 2008 and sent traffic information from each Dash owner for other drivers to see. (Research In Motion, which purchased Dash Navigation in 2009, discontinued Dash Express service and support on June 30, 2010, for undisclosed reasons.)
All this could lead to what Shulman calls the smart intersection. Cars would know the status of the next traffic light, the speed of other cars and that, say, there was a semi-trailer truck barreling down the cross street. Shulman says there are other benefits unrelated to safety: Drivers could look up the routes they have taken over several weeks or track their miles per gallon from a computer.
Of course, getting car companies to decide on and conform to an approved standard for car communication may be a challenge. Another challenge is that wireless signals can be unreliable in moving vehicles. For example, Wi-Fi, which is just starting to become available in cars such as the 2011 Ford Edge, requires complex algorithms to make sure it works well in a moving vehicle.
It's too soon to tell whether the DSRC signals on the 5.9-GHz spectrum will have reliability problems, but there's no doubt that automakers will need to test and retest the communications systems to ensure uptime and accuracy.
Finally, as AutoPacific's Kim notes, no amount of vehicle-to-vehicle communication will help when drivers make monumental mistakes, such as driving into a tree.
Collision avoidance systems
To help reduce fatalities, cars' computers will help drivers avoid crashes in the first place. Adaptive cruise control, which adjusts car speed automatically as you approach another car on the highway; blind-spot warning systems, which use cameras or sensors to detect cars moving up beside you; and lane-departure warning systems, which alert you when you drift out of your lane, are already fairly common. (Read about these features in our earlier story, "Car tech: Taking drivers' helpers for a spin.")
Next up are collision avoidance systems that inspect environmental variables such as road conditions, lane markers and your attention level (by measuring steering wheel movements, time elapsed since you started the car, erratic behavior and many other variables) and use advanced algorithms to determine how much you should be braking in a given situation.
Already in use in advanced vehicles such as the Acura RL, the Mercedes S550 and the Volvo S60, these systems send out a radar signal and wait for a response to determine the distance and closing speed of cars and other objects in front of the car. If a collision is likely to occur, the car first warns the driver, then automatically applies the brakes partially or fully, depending on the time to impact.
