Cost to be big factor in 'talking' cars acceptance: U.S. transport chief ANN ARBOR, Michigan (Reuters) - Cars that "talk" to each other to avoid crashes or traffic jams, like those being tested here, will save lives but the cost of the systems will determine consumers' acceptance of such technology, the U.S. transportation secretary said on Tuesday. These are definitely safer vehicles. At what cost though? Ray LaHood told reporters at a connected-vehicle conference in Ann Arbor, Michigan. To me, that's what the bottom line's going to be. Safety has a cost and we're going to have to make that judgment. LaHood declined to estimate what the cost of the technology that allows vehicles to communicate with each other and surrounding infrastructure would need to be to attract wide adoption by consumers. "It will be up to car manufacturers to help us figure out what the cost of all this is going to be," LaHood, the outgoing transportation chief, said at a University of Michigan Transportation Research Institute conference. Since last August, U.S. officials have been testing a fleet of "talking" cars in Ann Arbor that may help American drivers avoid crashes and traffic jams. The U.S. Department of Transportation and the University of Michigan fitted almost 3,000 cars, trucks, buses and motorcycles with wireless devices that track other vehicles' speed and location, alert drivers to congestion, or change a traffic light to green. Vehicle-to-vehicle communication may help avoid or reduce the severity of four out of five crashes that occur when a driver is not impaired, U.S. regulators have said. Results from the study will help the National Highway Traffic Safety Administration decide whether the technology should be mandatory. A decision on such a rule will not be made until the testing in completed in August, officials have said. LaHood said transportation officials have been studying the first six months of data from the test, but he does not expect any conclusions for about a year. He said the technology has operated just as officials expected. Officials in the test program said about 8 billion transmissions between vehicles and infrastructure have been sent since the test in Ann Arbor began. The road test in Ann Arbor, a college town of nearly 28 square miles (73 square kilometers), is the largest of its kind and cost $25 million. Eight major automakers, including General Motors Co and Toyota Motor Corp, supplied the cars. The vehicles in the test can communicate with roadside devices in 29 areas in Ann Arbor. If conditions are safe, the vehicles can change the traffic light to green or let the driver know if a light is about to change. Connected vehicle systems use a technology similar to Wifi called dedicated short range communication, which is unlikely to be vulnerable to interference, U.S. officials said. The cars can track other cars' location and speed. They can also determine if a driver is braking or turning the wheel. Details such as the license number or VIN number are not shared. The road test represents the second phase of the transportation department's connected vehicle safety program. In a study conducted in 2011 and early 2012, the department found that nine out of 10 drivers had a "highly favorable" opinion of vehicle-to-vehicle technology. LaHood said he assumed there would be a third phase in the testing. Reporting by Ben Klayman; Editing by Vicki Allen