Driving through Northern Virginia, it's quite rare to see yards with signs revealing that a homeowner plans to vote both Republican and Democrat on Nov. 6.

Even if they don't openly proclaim their split-ticket status, they're out there, according to polling.

These "split ticket voters" plan to step into the polling booth on Election Day to vote for a Republican and a Democrat: Voting for President Barack Obama and Republican Senate candidate George Allen, or for Republican presidential candidate Gov. Mitt Romney and Democratic Senate candidate Tim Kaine.

"It is a real possibility that Romney could win Virginia while George Allen loses," said Mark Rozell, professor of Public Policy at George Mason University. "Some polls have shown that Tim Kaine runs slightly better than President Obama in the state, suggesting that there is a small but notable percentage of potential split-ticket voters."

Part of the reason, Rozell said, "may be that George Allen's image still suffers from the events of his unexpected loss in 2006. Also, Tim Kaine has been running a bit to the right of Obama on some issues and has carved out some swing voter support that the president may not be getting right now. It may be a small percentage, yet enough to carry Kaine, even in an Obama loss in the state."

"It is hard though to imagine a combined Obama and Allen victories scenario," Rozell said.

Overall, voters have split their ballots in presidential and U.S. Senate races less than 30 percent of the time since popular vote senatorial races were introduced about a century ago, doing so in just 245 out of 829 elections (29.6 percent), according to the Humphrey School of Public Affairs at the University of Minnesota.

Kaine told The New York Times this summer he thought he could appeal to Romney supporters.

“There will be thousands of Romney-Kaine voters,” Kaine said in the story. “Whether it will be 2,000 or 50,000, I don’t know.”

Kaine campaign aides told the newspaper that they would find Romney-Kaine voters in the suburbs of Washington and Richmond, where voters might see Kaine and Romney as pro-business technocrats, and Allen and Obama as partisan flag carriers for their parties.

The National Journal puts it this way: "...in the Northern Virginia suburbs, voters who care about transportation issues as much as anything else, might be inclined to register their disapproval of Obama — especially with the pending budget sequester threatening defense industry jobs — but also to stick with Kaine."

More than six in 10 ticket-splitters are younger independents, according to polling, National Journal says:

• under 50 years old (while the electorate as a whole is split evenly between those over and under 50)
• self-identified independents, with whom Kaine outperforms Obama.

University of Virginia's Larry Sabato says the presidential and Senate races across the country are not related. “Right now these [Senate] contests are running on different tracks,” he told the Washington Times earlier this month. “Sometimes you have [presidential and Senate races] on parallel tracks. I don’t think these are right now. But they will be to a greater extent on Election Day.”

In previous years, here's how Virginia voted:

• 2000: Virginia voted a straight Republican ticket, voting for candidate George Bush and Republican candidate for Senate, George Allen, according to Virginia State Board of Elections records. Fairfax County voted for Bush and Democrat Chuck Robb, according to SBE records.
• 2008: Virginia and Fairfax County voted a straight Democratic ticket, voting for Obama for president and Mark Warner in a Senate race.

In 2006, with no presidential race, Jim Webb bested Allen, 49.59 percent to 49.20 percent for the Senate seat.

For complete election coverage of both state and national elections from a Northern Virginia perspective, click on the elections tab at the top of the page.