The Subaru Outback sedan looks like any other midsize car, with a trunk and comfortable seating for four adults.

But Subaru is tweaking some parts of the Outback sedan and wagon this year to meet the specifications of a light truck, the same regulatory category used by pickups and sport utilities. Why? Largely to avoid tougher fuel economy and air pollution standards for cars.

It is the first time an automaker plans to make changes in a sedan -- like raising its ground clearance by about an inch and a half -- so it can qualify as a light truck. But it is hardly the first time an automaker has taken advantage of the nation's complex fuel regulations, which divide each manufacturer's annual vehicle fleet into two categories. Light trucks will have to average only 21.2 miles a gallon in the 2005 model year. By contrast, each automaker's full fleet of passenger cars must average 27.5 miles a gallon.

The move will let Subaru sell more vehicles with turbochargers, which pep up performance but hurt mileage and increase pollution. ''It was difficult to achieve emissions performance with the turbos,'' said Fred D. Adcock, executive vice president of Subaru of America. They also made it hard to meet fleetwide fuel economy standards for cars.