Anti-tax Republicans in Fairfax County have launched a last-ditch campaign that includes a 30-second television ad urging voters to defeat a transportation bond proposal that would raise $110 million for Metro.

The Fairfax County Taxpayers Alliance, the Virginia Club for Growth and some local politicians say the bond measure, which also includes $55 million for roads, is a giveaway to a troubled Metro system that serves only a fraction of the county's population.

The bond proposal on Tuesday's ballot and the campaign against it are part of a debate over whether the region's transportation network would be best served by more roads or more rail. Limited transportation funding in Virginia and Maryland has forced leaders to choose between upgrading roads and giving money to a Metro system that its managers say will rapidly deteriorate without substantial investment.

In the ad, which will run on Fox News, CNN and MSNBC in Fairfax through Monday, state Sen. Ken Cuccinelli (R-Fairfax) implores residents to defeat the measure.

"We need real solutions in Fairfax, but on November 2nd, you'll be asked to spend bond money on a mismanaged Metro system," he says, standing in front of an intersection. Cuccinelli goes on to say: "Metro pays bus drivers $67,000 a year. That's more than our teachers."

Road advocates contend that highways are far cheaper to build and maintain and can support rapid bus service that they say is comparable to rail service. Rail proponents say that Metro and other regional systems are a critical part of efforts to reduce regional congestion and air pollution and that they also form hubs for well-planned communities.

Fairfax County has five Metro stations, where about 86,000 riders get on and off the system each day. The first phase of a proposed rail extension to the Dulles area would add five stations, including service to Tysons Corner.

The people opposed to the ballot measure helped defeat a regional proposal two years ago that would have raised sales taxes to pay for $5 billion in road and rail projects over 20 years. But this time around, opposition leaders acknowledged that they got a late start, and they said they would be satisfied with changing a few minds, if they can't persuade a majority to vote no.

"We're starting late, and this is a tough battle to win," Cuccinelli said. "Hopefully, we can make a dent in the score."

The two sides in the debate cite Metro's service problems -- crowding, delays, breakdowns -- either as proof of the need to buy better equipment and expand the system or as a reason to stop throwing good money after bad.

"Taxpayers shouldn't be asked to foot the bill for Metro's poor budgeting and poor decisions," said Cuccinelli, who added that Metro needs to "clean house," get rid of its union rules and raise rates to meet costs.

Metro officials have warned of a possible rate increase next year, which would be the third in a row for an increase.

The 30-second spot was paid for by the Club for Growth and cost $5,000 to make and air, club officials said.

"Only 4 percent of Fairfax residents use Metro on a daily basis," said Peter Ferrara, president of the Club for Growth. "To incur debt of $110 million for something that will only make a marginal difference is an unfair burden on taxpayers."

Fairfax Board of Supervisors Chairman Gerald E. Connolly (D) said Metro's problems show that it "is working, but just like anything else, to make sure it continues to work, we have to make some investments."

Connolly said opponents of the bond measure are part of a "do-nothing crowd" that makes hollow promises to improve transportation while opposing any money-raising venture. "They are selling snake oil, and it won't work," he said.

Arlington County residents also will decide whether to approve ballot measures that would raise $18.5 million for Metro and $10.2 million for other transportation initiatives.

Arlington officials said they would use a combination of bond money and state money to meet a $79.6 million, six-year commitment to Metro.