Michigan, USA - IN a few weeks, about 2,800 cars, trucks and buses will start talking to each other on the streets of Ann Arbor, Michigan, in a giant experiment that US government officials are hoping will lead to safer roads.

Wireless devices will allow the vehicles to send signals to each other, warning their drivers of potential dangers such as stopped traffic or cars that might be blowing through a red light. They can even get traffic lights to turn green if no cars are coming the other way.

The US Department of Transportation and the University of Michigan are hoping the year-long, US $25-million project generates data that show the devices can cut down on traffic crashes. Officials say eventually this could lead to the devices going in every car. About 500 vehicles with the devices are now on the roads. That will rise to 2,800 in about six weeks, officials said yesterday.

"This is a big day for safety," Transportation Secretary Ray LaHood said at an event at the university formally kicking off the experiment. "We'll use this information to decide if vehicle technology can be applied to daily lives."

More than 32,000 people died last year in US traffic crashes, down 1.7 per cent from 2010. The number of crashes has fallen in recent years as automakers added safety devices such as air bags, antilock brakes and stability control, which helps drivers keep cars under control in emergency situations.

LaHood said yesterday that 80 per cent of crashes in which the drivers aren't impaired by drugs or alcohol could be prevented — or the severity reduced — if cars could talk to each other.

No one knows exactly when the technology will make its way into cars and trucks everywhere. LaHood said the National Highway Traffic Safety Administration will look at the data before deciding to require the devices. The data needed to make a decision will be available in a year.