“It’s just a few blocks to the Metro.” Despite wearing countless layers of tights and fleece-lined tops, I’ve had to tell myself that every day this week to summon the courage to walk out my front door.

Driving isn’t an option for me, so that remains a fantasy — like a hand warmer that could envelope my entire body. (That would have sold so well on Inauguration Day!) But for people with a car and a free parking spot at the office, not much is stopping them from getting behind the wheel. And the problem with that, at least from a pro-transit perspective, is that it’s just as true on perfectly pleasant days as it is during the rare wintery blast.

Just before Washington witnessed Obama’s second swearing-in, the city hosted another important occasion: the 92nd annual meeting of the Transportation Research Board. Among the thousands of presentations that were part of the conference, one that caught my attention was a study by Ralph Buehler, an assistant professor of urban affairs and planning at Virginia Tech, and doctoral student Andrea Hamre.

Role of Commuter Benefits in Shaping Decision to Walk, Cycle, or Ride Transit to Work in Washington, D.C., Region” relied on data collected by the Metropolitan Washington Council of Governments’ 2007/2008 Household Travel Survey. One of the things it tabulated was the transportation perks that folks in the region get with their jobs. And what Buehler and Hamre found is that benefits such as cash for public transit, bike racks and access to showers don’t matter much if there’s also an inviting space for your car.

“In the presence of free parking, the efficacy of other modes is blunted,” Hamre says.

To be clear: It’s not that transit benefits and cyclist/pedestrian amenities don’t work. It’s that they don’t work nearly as well when people also have free parking at work.

Some people have to drive, whether it’s because of where they live or their specific job responsibilities. But given all of the bad stuff that comes along with driving — stinky air, higher rates of obesity, gridlocked streets — it seems counterproductive that more than a third of the group surveyed had free parking at work.

Buehler suspects no employers will be getting rid of free parking anytime soon, particularly in buildings and neighborhoods with an abundance of garages and lots. So the only way to overcome the car’s advantage is to beef up the other benefits.

It seems to me that if you paid folks to wait at the bus stop, they’d be more willing to do it. Or what if cyclists got an extra vacation day? Or walk-to-workers had discounted health insurance?

These proposals all cost money, but so does maintaining a parking garage. And there has to be some way to make car alternatives more attractive — except maybe in 15-degree weather.