Location: Seattle, WA

Through boom and bust, and despite steady population growth, total gasoline consumption in Oregon and Washington has remained essentially flat since 1999, according to a new report from Sightline Institute. Yet the two states still spent $16.6 billion on petroleum in 2010 and are on track to spend as much as $22 billion this year—an all-time record.

Although regional gasoline consumption reached a plateau just over a decade ago, per-capita consumption has been declining since 1989. Person-for-person, Northwesterners use less gas today than at any point since 1965. Meanwhile, total car and truck travel has been stuck in neutral since 2002, after previous decades of steady growth. The findings raise the possibility that the region may already have reached “Peak Gas,” with gasoline consumption remaining stable or declining for the foreseeable future.

Rising and more volatile fuel prices, demographic shifts, and fuel efficiency gains are among the reasons for the flat consumption. “Today’s shaky economy is only part of the story, since gas consumption fell flat long before the recession began,” said Clark Williams-Derry, author of the report. “It’s a trend that has crossed economic booms and busts alike.”

The last decade’s steady consumption coincides with an era of increasingly expensive and volatile fuel prices. Gas prices were stable and declining during most of the 1980s and 1990s, and gas consumption grew quickly. But once prices started rising in the late 1990s, fuel consumption flattened out.

Other cultural and demographic changes may also be involved. Baby Boomers are moving past their peak driving ages, and younger generations are foregoing car ownership—or even getting a driver’s license—until later in life.

The trend has big implications for transportation finance. Oregon and Washington are both considering major bridge, tunnel, and highway megaprojects, and are counting on robust gas tax revenue to help pay for them. Falling gasoline sales and fewer miles traveled could lead to revenue shortfalls, placing transportation finance in jeopardy.

“But there is good news in the data,” said Williams-Derry. “Declining gas consumption means more money stays here in the Northwest.” Of the money spent on petroleum products, nearly all of it leaves the region. Flat gasoline consumption also means steady, but at least not increasing, greenhouse gas emissions responsible for warming the atmosphere and disrupting the climate.

Sightline Institute is a regional research and communications center working on sustainability issues across the Northwest. Clark Williams-Derry, author of the report, is Director of Programs at Sightline.

September 14, 2011