As police in Philadelphia struggle to stop a scourge of shootings, some New Jersey engineers say they are closing in on a 'smart' solution: a gun that can be fired only by its owner.

The prototype, developed at the New Jersey Institute of Technology in Newark, has pressure sensors embedded in the gun handle that recognize a person's unique grip.

The team says a commercial model is up to five years away, but if it works, it will trigger a singular - and controversial - state law. Within three years, all handguns sold in New Jersey would have to be personalized, with this or some other recognition technology.

Michael Recce, who dreamed up the grip-recognition concept in 1999, said the only obstacles are time and money.

'It's an engineering problem, not a scientific problem,' he said.

However long it takes, it's safe to say the university has embarked on a product-development quest like no other - wading into a contentious issue on the fault line between red and blue America.

Various smart-gun efforts have flamed out in the past, amid vocal skepticism by the National Rifle Association. Many gun owners chafe at the notion of any restrictions on their Second Amendment right to bear arms, and warn that any such modifications would make guns more expensive.

Gun-control advocates, meanwhile, are split, with some warning that personalized firearms would give owners a false sense of security.

Most see New Jersey's 2002 law as a commonsense safety measure, but they are starting to run out of patience.

'These guns should have been developed 20 years ago,' said Bryan Miller, executive director of Ceasefire New Jersey.

Duke University economist Philip J. Cook estimates that if all handguns were personalized, more than 4,000 lives would be saved each year from fewer murders, accidents and teen suicides.

Though the New Jersey law exempts law enforcement, police might also benefit from the technology. According to FBI statistics, as many as one in six officers killed each year is slain with his or her weapon.