Fewer Tickets to Ride

Tour companies have also struggled under increasing fuel costs. Naso said he spent about $3 a gallon on diesel gasoline last year for the five tour boats in his fleet. Last week, he paid $4.29 a gallon to fill up one boat's 3,800-gallon tank.

Naso has sought ways to offset the increase without scaring away customers. The company tacked on a 3 percent fuel surcharge to each ticket in the past year. But in a nod to increasingly frugal customers, it plans to offer regular, two-hour midday tours starting next week that are cheaper than its traditional dinner cruises.

Naso has also slowed down the new Seadog speedboat that travels to National Harbor -- a half-knot decrease almost imperceptible to riders but which increases fuel efficiency.

"Everybody feels the same pinch," he said.

At Open Top Sightseeing, each red double-decker tour bus holds about 120 gallons of gasoline and needs refueling every other day. The company runs 11 buses that clock 100 miles daily. The route starts at Union Station and stops at the White House, Adams Morgan and Arlington National Cemetery.

"We can feel it like everyone else," said Anders Nielsen, U.S. development director for Open Top's parent company, Les Cars Rouges. He may not be able to put extra buses on the route during busy times this year and plans to train drivers on how to improve mileage.

Fleet Transportation in Alexandria has begun working with consulting firm Green Ride Global to help it become more fuel-efficient. It now requires drivers to switch between idling their engines for one minute and turning them off for 10 minutes, to conserve fuel when waiting for passengers. The optimum driving speed is 50 to 55 miles per hour, and jumping from 20 to 70 mph when entering the Beltway is discouraged.

Stacey S. Glazier, director of sales and marketing, said Fleet has already seen some cost savings, and the changes have been a selling point to both private groups and corporations.

"We can offer you that sense of extra-conscious effort," she said.

But will $4 gas keep people from driving and companies from making money? The Car Care Council isn't taking any chances.

An industry group that promotes auto maintenance, the council released this news alert last month: "Traditional summer family vehicle vacation better deal than flying."

The council extolled the benefits of driving: leaving at any time, no long security lines and the chance to stop and stretch at any moment. Even if fuel were to hit -- gasp! -- $5 per gallon, the council estimated that a 1,000-mile round trip would cost a family of four riding high in an SUV about $343.

"The thought of sitting at home and forgoing that wonderful family road trip, and all the pleasures that brings and enjoying some beautiful country -- we certainly don't want to see people not doing that," Executive Director Rich White said. "It is an encouragement not to freak out."