A sophisticated, real-world study confirms that dialing, texting or reaching for a cellphone while driving raises the risk of a crash or near-miss, especially for younger drivers. But the research also produced a surprise: Simply talking on the phone did not prove dangerous, as it has in other studies.

This one did not distinguish between handheld and hands-free devices - a major weakness.

And even though talking doesn't require drivers to take their eyes off the road, it's hard to talk on a phone without first reaching for it or dialing a number -things that raise the risk of a crash, researchers note.