Until his head collided with a windshield, Ben Roethlisberger savored the liberty of riding a motorcycle without a helmet. Now the Pittsburgh Steelers’ quarterback says he has “a new perspective on life.”

“If I ever ride again, it certainly will be with a helmet,” he announced on Thursday, the day after leaving the hospital.

There’s a lesson here for libertarians — and don’t worry, it’s not that we must pass laws mandating helmets for everyone. There’s a better way to protect riders: libertarian paternalism, which is not as oxymoronic as it sounds.

The term was coined by a law professor and an economist at the University of Chicago, Cass Sunstein and Richard Thaler. They want to preserve your liberty to make choices, but they’d also like to improve your odds of choosing what you really want.

If Roethlisberger had done a sober cost-benefit analysis, he never would have gotten on a motorcycle. Even a minor accident — a spill that shattered his elbow — could have ended his career and cost him tens of millions of dollars.

Now he’s got a new perspective, and so do the many motorcyclists who will be wearing new helmets this weekend after the publicity about his accident. But their new perspective isn’t entirely rational, either. Their odds haven’t changed just because of one accident. Why should they start wearing helmets now?

Because they’re making decisions the way most humans do — haphazardly. We’re guided more by one recent horror story than by reams of statistics. Unless pressed, we tend to avoid thinking about unlikely events, like traffic accidents, or problems in the distant future, like how we’ll finance our retirement.

We’ll choose something simply because we think it’s what most other people would do. Our decision often hinges not on the facts but on how the facts are presented: if told there’s a 10 percent chance of dying from a medical procedure, we’re less likely to go ahead with it than if we’re told there’s a 90 percent chance of living.

Given all these foibles, Sunstein and Thaler argue, it’s naïve to assume that people are making fully informed choices. Since people’s choices often depend on how the options are presented, authorities should practice a mild form of paternalism: point people toward what experts think is best for them, but don’t force them to go there.

This might mean simply providing the public with information and advice. Or it could mean changing the options available, as was done in experiments with 401(k) plans. Instead of giving workers the traditional option to enroll in the plans, employers automatically enrolled everyone and gave them the option to withdraw. As a result, far more workers set aside money for retirement.

How would you apply this libertarian paternalism to motorcycle helmets? I consulted Sunstein and Thaler, as well as Edward Glaeser, a Harvard economist who’s more skeptical about this approach. He worries that bureaucrats and politicians are prone to making their own bad decisions when they turn paternalistic. They’ve made it their business to stigmatize certain behaviors, like homosexuality, and they’ve deluged people with dubious guidance, like the changing edicts on what Americans should eat and how much they should weigh.

But Glaeser does see a role for paternalism when dealing with a problem as clear-cut and serious as motorcycle fatalities. He, Sunstein and Thaler like the idea of encouraging cyclists to wear helmets by changing the options they face. Instead of telling them that a helmet is optional — the default situation in most states — tell them a standard license comes with the requirement to wear a helmet.

If a libertarian cyclist objected, he could apply for a special license to ride without a helmet (along with a decal for the motorcycle so the police wouldn’t stop him). He’d have to provide proof that he carried enough insurance to cover the costs of an accident so that taxpayers wouldn’t get stuck with the bill. And he’d have to learn about the risks, perhaps by attending a short class or watching a video of it on his home computer.

The class shouldn’t be an exercise in fear-mongering. It could include testimonials from intelligent motorcyclists who’ve weighed the risks and still want the joy of the wind on their faces. But before anyone gets this license, he ought to see a good analysis of the injury statistics and hear about the benefits of helmets — including that new perspective from the Steelers’ quarterback.

Maureen Dowd is on vacation.