Along I-95 in Maryland, rest stops come with fast-food restaurants and gas stations. Along I-95 in Virginia, they have orange barrels that block anyone from entering. The difference is all due to one pesky law that Virginia and a number of other states want to change.

Currently, the only commercial activity allowed in most of the nation's rest stops happens through vending machines. That restriction is part of a federal law that dates back to the early days of the Interstate Highway System. One-quarter of the states, including Maryland, had roadside commercial operations grandfathered into the law. They're glad they did: Today, Maryland brings in millions of dollars per year just from Chesapeake House and Maryland House, the two massive "travel plazas" north of Baltimore on I-95.

Virginia would like to get its hands on that kind of cash. Facing a shortfall in its transportation budget, it tried to persuade Congress to overturn the old rest-stop law and allow it to lease out the valuable space along its major highways. When the effort died in committee this summer, Virginia shuttered 18 of its 42 rest stops--including, somewhat pointedly, the busy stops closest to Washington, D.C., and the U.S. Capitol.

The debate seems likely to come back, in part because Virginia isn't the only state looking to change the law. California, Oregon and Washington State want to build a network of alternative fuel stations at rest stops along I-5, but they, too, are blocked by the ban on commercialization. The states are facing surprisingly entrenched opposition. A coalition of fast-food chains, gas stations and convenience stores known as the Partnership to Save Highway Communities argues that rest-stop commercialization would jeopardize investments in franchises located off highway exits.

For now, that argument is winning the day in Congress, much to the chagrin of Virginia officials. "We're not talking about putting up a mall," says Gordon Hickey, spokesman for Governor Tim Kaine. "We're talking about a place where someone can buy a drink and a sandwich and be on their way."