PITTSBURGH (AP) _ Coach Bill Cowher is worried the Pittsburgh Steelers' winning streak is about to end not on the football field, but at the ballot box.

So Cowher threw a change-of-pace into his weekly news conference Tuesday, delaying his usual remarks to plead with fans to approve a temporary tax increase to fund new stadiums for the Steelers and Pirates.

Voters in 11 western Pennsylvania counties will decide Tuesday whether to raise the sales tax, currently 7 percent in Allegheny County and 6 percent elsewhere, by half a percentage point for seven years.

The hike would be relatively modest, increasing the average family's tax bill by $55 a year. But it is meeting with strong opposition in a region whose aging population _ only Dade County, Fla., has an higher median age _ is already among the nation's most heavily taxed.

Newspaper polls taken last week show the referendum trailing by double-digit margins _ an improvement from 3-to-1 opposition in May, but a huge gap to close in only a week.

``It's definitely the fourth quarter and we're definitely under two minutes,'' Cowher said. ``I don't know the score. I know what everyone else says (that it will fail), but I know where I stand on it.''

The tax increase would partially pay for the new stadiums, a rebuilt convention center and cultural district and other projects designed to attract businesses and jobs to a region that has steadily lost population since the 1960s.

The NFL has won seven consecutive votes in other cities to build stadiums, including Cincinnati, one of Pittsburgh's AFC Central rivals.

Still, despite the Steelers' overwhelming popularity, putting a tax hike on the ballot is a risky proposition in a city where the owner of a $150,000 home pays about $4,000 a year just in school and property taxes.

``Obviously it comes down to $55 or $60 a year, but that's not the issue, it's the principle ... the common bond that sports brings,'' Cowher said. ``You come into the city on a Monday after a (Steelers) win and it's a very uplifting atmosphere.''

Team owner Dan Rooney has never threatened to move the team that his father founded 64 years ago. But with the Steelers already near the bottom of NFL franchises in revenues, and with all of their division rivals soon to be playing in new stadiums, he isn't promising to keep them there forever.

``As those teams double or triple their revenues, it will place us even further behind if we do not get a new stadium,'' Rooney said. ``As the revenues of the other teams increase, the salary cap goes up while the Steelers' revenues remain stagnant. But we still have to compete for the same players.''

Cowher said, ``It's hard to imagine Dan Rooney somewhere else, but you have to look around the league and see the reality of what's taking place. You hate to see anyone put in a situation where they have no choice.''

The tax hike would pay about half the cost of a proposed $200 million stadium, to be built about a block from Three Rivers Stadium.

Rooney has pledged to contribute $50 million and pay for any cost overruns. Such overruns are a big issue in Cincinnati, where the Bengals' new stadium has doubled in cost from $200 million to about $400 million.

Cowher joked Monday with Chiefs coach Marty Schottenheimer, his former boss, that Monday's game may decide the Steelers' future.

``I told him it was pretty important that we win the game because the vote was the next day, and it would have a lot to do with sports staying in this city for a long period of time,'' Cowher said. ``I didn't want him to feel guilty or anything (if the Chiefs lost).''