In a win for the Seattle Monorail Project, a judge today rejected claims that the agency's car-tab tax is arbitrary and unconstitutional.

Basically, the tax is legal because voters approved it in 2002, according to Judge William Downing of King County Superior Court. He issued a summary judgment, without the jury trial agency opponents requested.

The plaintiffs argued that the monorail's motor vehicle excise tax (MVET) is arbitrary because the bills are based on a state depreciation table that is higher than market or "Kelley Blue Book" value.

Downing said the issue is "of no moment" legally:

"... this court must conclude that Seattle voters approved an MVET calculation that was based upon the statutorily established valuation methodology rather than upon the expectation of a curbside appraisal of each individual Ford or Ferrari with its added dings and dents, woofers and tweeters," he wrote.

The lawsuit was filed by eight Seattle vehicle owners. Their legal team include Henry Aronson, who led the anti-monorail campaign in 2002.

The state Department of Licensing, which collects money on behalf of the monorail agency, has said a value-based system would require costly inspections.

But in a legal brief for plaintiffs, Jane Liu, a vice president of Edmunds.com, said her company is capable of supplying true market values that include variations in mileage, equipment, and regional variations.

And the manufacturer's suggested retail price, the basis for the tax table, is 8 percent higher than what car buyers really pay, said Liu.

Monorail opponents also argued that the tax is unconstitutional, because only two of the nine monorail board members are elected by the public, and seven are appointed.

Downing said the structure was approved by voters. "The court cannot find the slogan 'taxation without representation' to fit these circumstances," he said.

The monorail plan passed with a 50.2 percent yes vote in 2002.It was upheld in 2004 when 63.5 percent of city voters turned back an initiative that would have gutted the project.

The tax, averaging $130 a year, applies to cars at least one year old that are owned by residents of Seattle.

Monorail Finance Director Jonathan Buchter has said the case creates uncertainty in financial markets, impairing the effort to sell $1.7 billion in bonds for the proposed Green Line, a 14-mile route from Ballard to West Seattle.

"The judge couldn't have been more clear in dismissing the claims," monorail spokeswoman Natasha Jones said. "I think it just really helps us."

Both sides have said they expect an appeal.

Anti-monorail lawyers were not immediately available for comment.

Monorail activist Peter Sherwin said he hopes the car-tax case goes straight to the Supreme Court and is resolved quickly.

"We've got a project that may or may not go. We're on the cusp of finding out. So let's have some certainty," he said.

Meanwhile, negotiations continued today between monorail leaders and Fluor Enterprises, a lead contractor proposing to build the line. On Wednesday night, monorail board members will consider whether to set a deadline.

Mike Lindblom: 206-515-5631 or mlindblom@seattletimes.com