People who talk on cell phones while driving, even using "hands-free" devices, <A HREF="http://news.zdnet.com/2100-1035_22-6089908.html?tag=zdnn.alert">are as impaired as drunken drivers,</A> researchers said Thursday. The researchers studied 40 volunteers who used a driving simulator four times--while undistracted, using a handheld cell phone, using a hands-free cell phone and while intoxicated to a 0.08 percent blood-alcohol level--the average legal level of impairment in the United States--after drinking vodka and orange juice. Three study participants rear-ended the simulated car in front of them. All were talking on cell phones and none was drunk, the researchers said.