Saying "we told you so" can be a satisfying moment but not now, not with this grim news. A University of Pittsburgh study has confirmed what common sense and experience had warned: When a state repeals its safety law on helmets for motorcyclists, it unnecessarily dooms riders to death or serious injury.

That is what the Legislature did in 2003, repealing a law that existed for 35 years. The laws of physics, however, could not be repealed. When the human brain has no more protection than the skull and is thrown in a crash onto the hard surface of a roadway, it can fare no better in the fall than a yolk in an eggshell.

Lawmakers and Gov. Ed Rendell ignored the warnings. They were beaten down by the annual rallies of motorcyclists at the Capitol who demanded the freedom to be irresponsible -- and never mind that the state has always required those driving machines on the road to do so with the greatest regard for safety. That is why there are speed limits. That is why motoring when addled by alcohol or drugs is forbidden. No right of personal freedom covers such recklessness.

Driving is a privilege, not a right, and the social cost of letting motorcyclists indulge themselves by riding without approved safety gear is now beyond argument. The first evidence emerged in 2006 when the state Legislative Budget and Finance Committee, fulfilling a request made by lawmakers when they repealed the helmet law, reported a 33 percent increase in trauma center admission rates for motorcycle-related head injuries and an 11 percent rise in deaths.

The latest evidence is both more comprehensive and more alarming. By looking at discharge data from all acute-care hospitals for the two years preceding the helmet law repeal and the two years following, researchers from several of Pitt's Schools of Health Sciences found a 32 percent increase in head injury deaths and a 42 percent increase in head injury hospitalizations among motorcycle users.

The Pitt study did something else: It put startling dollar figures to the cost of the carnage. The number of motorcyclists with head injuries requiring further care at facilities for rehabilitation and long-term care jumped 87 percent after repeal. Acute-care hospital charges for motorcycle-related head injuries rose 132 percent, reaching $124.2 million in the years 2004 and 2005.

Guess who pays? We all do. As the ancient wisdom tells us, no man is an island. Every motorcyclist who claims it is his (or her) right alone to decide whether to wear a helmet and then crashes and suffers a needless brain injury drags so many others into the tragic equation -- the paramedics and police responding to an emergency, the doctors and staff at hospitals, the devastated relatives and friends. All this work and pointless misery, the sacrifice heaped upon the altar of personal freedom, plays out to the steady ticking of rising health-care costs that all of society pays in the end.

To object to this is not to embrace a nanny state. It is to stand up for common sense and responsible behavior. It's very clear now that Pennsylvania made a tragic mistake in 2003. If Gov. Rendell and lawmakers are content with this legacy of blood and tears needlessly shed, they should do nothing.

But if they have a conscience and consider the plain evidence, they should pass House Bill 945, sponsored by Rep. Dan Frankel, D-Squirrel Hill, which would make helmets mandatory once again. Otherwise, "we told you so" will go on being joylessly repeated with every new and avoidable tragedy.