In a public split, the Obama administration's pointman on transportation sharply disagreed with a proposal by a top US transportation safety investigator for a ban on hands-free calling while driving.Transportation Secretary Ray LaHood, who has made distracted driving his signature safety issue, said the focus should be on texting and hand-held cell calls, not fast-growing new technology that allows drivers to talk while keeping their hands on the wheel.LaHood said: "That is not the big problem in America. Most people don't put Bluetooth or Sync in their cars because they can't afford it. Everybody has a cell phone in their hand and it's held up to their ear while they're driving."National Transportation Safety Board Chairman Deborah Hersman issued a sweeping proposal last week for states to outlaw cell use while driving, including hands-free devices, except in emergencies. Use of motorist assist programs, such as OnStar by General Motors, would still be permitted.HANDS-FREE PRODUCTSHersman's board has no rule-making authority, but its recommendations can carry weight with lawmakers and regulators. Safety experts say any blanket ban was unlikely because it would be difficult to enforce.LaHood has discussed hands-free technology with automakers, but has never asked them to stop putting it in vehicles.LaHood said: "Our efforts are good laws and good enforcement, and personal responsibility. We'll work with anyone who wants to get on board."Distracted driving killed more than 3000 people in the United States in 2010, Transportation Department figures there show.Vehicle companies are heavily investing in hands-free wireless products, like Bluetooth or Ford's Sync communications and entertainment system. Consumer experts say hand-free systems have become decision-makers for some consumers, especially younger buyers.