The upscale grocery store near my home in Tenleytown is a popular spot for foodies. Most of these “diehard” environmentalists roll up in their cars because the store has made it quite convenient to do so. I choose not to drive, and I don’t fault those who do — as they’re paying for their choices. But at this grocery store, and many others across the nation, drivers do not bear the true economic costs of their choices, let alone the environmental ones. Instead, the supermarket takes the cost of providing the parking and, since we all pay the same prices for grocery items, redistributes it among everyone who shops there. In effect, cyclists, walkers and those who take public transit subsidize the parking of those who don’t.

In the District, where all too many people drive, parking is a scarce commodity, and it commands a high price when its cost isn’t hidden. Even though this grocery store (okay, it’s a Whole Foods) must pay for leased parking that would amount to thousands of dollars a week at normal market prices, parking is free for store patrons. Despite encouraging customers to “go green,” Whole Foods and many other chains encourage driving by artificially reducing the cost of doing so.

Parking isn’t the only driving incentive that is provided by grocery chains. Stop & Shop, Giant, Safeway, Price Chopper and other stores have deals with gas stations that give customers per-gallon discounts when they purchase a certain amount of groceries. The cost of such programs is simply incorporated into the prices on the shelves. Environmentalists and those who cannot afford to drive end up making it easier for other customers to shop by automobile.

Many in the environmental movement would like to see the big ecological costs of polluting decisions (what economists call externalities) reflected in the price of goods and services through such governmental policies as a federal carbon tax. But simply removing the hidden economic costs of polluting activities would be a good start. The District’s 5-cent bag tax did just that by forcing customers, and not grocery stores, to pay for checkout bags. In truth, paper and plastic bags were never “free”; it’s just that users weren’t footing the bill. Customers who brought cloth bags before the bag tax was established were essentially helping to pay for others to do the opposite. Now we pay for our bag choices, and people’s behavior has changed dramatically. Perhaps fewer people would drive if we reattached costs to driving that are now being offset by non-drivers.

When businesses eat the costs of environmentally burdensome decisions, those of us making sacrifices for the planet can end up having our actions nullified. Thus, when I ride my bike to pick up some fruit at the market, I make it easier for someone else to hop into his Range Rover for a three-block jaunt to grab some milk. If the true price of such trips had to be paid, perhaps more people would begin to make choices that would be better for their wallets, for their waistlines and ultimately for the Earth.

The writer is national advocate for Bicycle Benefits.