The number of riders on the Utah Transit Authority's TRAX system decreased about 17 percent in 2007 over the previous year, according to figures approved Wednesday by the agency's Board of Trustees.

But the significant decrease is a result of a new, more accurate way of counting riders, UTA officials said. The agency estimates its numbers from 2006 and years prior were overinflated and that ridership last year was on par with the previous year.

"It is our belief that TRAX ridership is probably flat when compared to 2006," said Jerry Benson, UTA chief operating officer. "What you're seeing is a 17 percent difference in the more accurate counting method."

UTA began using its new counting system in 2007. The system uses infrared monitors at the doors of each TRAX car that can count individual riders and keep track of where people enter and exit a train.

In prior years, UTA used a method where each month on random days, riders were counted manually in the lead car of a TRAX train. Ridership on the rest of the train was estimated off that count, leading to overinflated numbers, UTA said.

Benson said the old, manual method of counting is approved for use by the federal government and that many agencies across the nation still use this method. UTA decided to switch to the automated method because of increased efficiencies and the more accurate ridership counts, he said.

"We just didn't know how much more accurate it was until we put it into place," Benson said.

The ridership list approved Wednesday shows about 11.4 million riders used TRAX during the first 11 months of 2007. That amounts to about 40,294 average riders per weekday, according to UTA.

TRAX opponent Michael Packard said Wednesday the changing ridership numbers show deception by UTA.

"You fooled everyone," he said.

Packard is a longtime opponent of transit and frequently appears at UTA board meetings. He is a Sandy-based engineer.