WITH MASSIVE CUTS in transportation funds looming on the horizon, Portland is pumping the brakes—hard.

Last week, Portland's Bureau of Transportation (PBOT) said that it expects to cut $16 million from its budget next year. While this gap will leave PBOT officials scrambling to maintain roads, build bikeways, and repair sidewalks, it's also oddly a badge of success for our sustainability-minded city: the more Portlanders who go green and buy less gas, the more the transportation budget suffers.

Nearly half of PBOT's general transportation revenues come from the state gas tax—now at 30 cents a gallon after a much-debated January hike of six cents. And although that's not the only reason PBOT's budget is strained, it's a significant factor. Consider that the Portland Climate Action Plan aims to reduce vehicle miles traveled by 30 percent by 2030—contradicting PBOT's dependency on the gas tax. Additionally, the city's Bicycle Master Plan urges Portlanders to make 25 percent of their trips by bike by 2030.

"I'm thinking this is something we've known all along," says Elly Blue, a writer who runs the business PDX by Bike. Blue fears the city will look to cut "extras," including bike transportation funding, when dealing with the deficit. "But that's no long-term solution. This is a long-term problem."

PBOT spokesman Dan Anderson advocates taking a more thoughtful approach. "We need to make these [budget] cuts permanent. This is more than a quick-fix, one-time cut."

According to Oregon Department of Transportation [ODOT] spokesman David Thompson, the gas tax has generated far less revenue for Oregon than predicted. In the past five years, ODOT has consistently overestimated the yearly amount—this year, by five percent.

"The gas tax is clearly an unstable funding source," says PBOT's Anderson, adding that the bureau has already made significant cuts to close a deficit in the current fiscal year.

Blue says she sees several other funding sources in the city that PBOT could feed from, including making paid parking universal in Portland and—controversially—giving up on plans to pave neighborhood streets.

Michael Andersen, editor of news magazine Portland Afoot, suggested a mileage tax. "It's time to look at a new tax that doesn't depend on one particular form of fuel," says Andersen. "We need to make a shift. Funding is going to continue to be a problem as long as our system depends on gas consumption."