Will a series of road-choking and aggravating construction projects change that?

The people who organize car pools for a living hope so.

"Construction may be an excuse for people to try ride-sharing -- if you are frustrated with the congestion or frustrated with the parking," said Chuck Imbrogno, a transit specialist and models/data manager with Southwestern Pennsylvania Commission, a regional planning agency.

The University of Pittsburgh’s ride-sharing program has already received a handful of inquiries in anticipation of those dreaded orange barrels. G. Robert Harkins, Pitt’s director of parking, transportation and services, thinks the construction may help boost the university’s program -- but he is not sure by how much.

That’s because no one really knows how disruptive it will be to drive once the ramps leading to the Fort Pitt Bridge close this year.

"This Fort Pitt Bridge thing has been like ‘the sky is falling’ for the past six or seven years," Harkins said. "Until it really happens, I don’t think it will hit people in the head."

Most people zoom down the Parkway alone because they want the flexibility to stay late at the office or bolt out for a family emergency. Or they need to rush out of the office to pick up their children at day care.

Or maybe it’s those Oldsmobile Alero commercials that say, "Stop commuting, start driving" -- a campaign that gave Timothy C. Session a start. The ad goes against the philosophy of Session, the ride-sharing coordinator at the Southwestern Pennsylvania Commission.

Whatever the reason, people who carpool and vanpool are a small minority. About 70 percent of the people in the nine-county area (Allegheny, Armstrong, Beaver, Butler, Fayette, Greene, Indiana, Washington and Westmoreland) drive alone to work, according to a Southwestern Pennsylvania Commission study. That rate, Imbrogno said, is comparable to those in other cities.

People who commute to Downtown Pittsburgh, though, tend to share rides more.

Of the estimated 150,000 people who work Downtown, about half use mass transit, Imbrogno said. Of the remaining half, he said, about 20 percent use car pools or van pools and the remaining 30 percent drive alone.

Some people set up pools on their own with a friend down the street. Others go through the commission, which keeps a database of people, neighborhoods and hours of their commute. (Call 412-471-POOL).

People who fill out a ridership survey receive a list of names and street names of possible matches. To protect privacy, home phones or street numbers are not divulged. Participants are given work numbers and can call people on the list themselves.

The commission also helps coordinate the car- and vanpooling of nine corporations, including Mellon Bank, PNC Bank and Highmark Blue Cross-Blue Shield, and helps them set up other options such as flextime.

People who commute to Pitt or to other institutions in Oakland can find other riders by calling 412-624-0687. About 600 to 800 people, mostly staff members, are registered in the program. Commuters can either contact fellow commuters themselves or let Pitt make a match.

People who carpool save money by sharing such expenses as parking and gas. They also save on wear and tear on their vehicles and sometimes lower their insurance costs.

"Driving alone is always the most expensive option," said Kathleen Miller, administrator at Pitt’s department of parking, transportation and services. "I know people who drive a Toyota and they put $2 worth of gas in it a week and they think that is their total cost. It isn’t."

Another option is riding aboard a nine- or 12-passenger van, something that Imbrogno said makes economic sense only if your commute is 15 miles or more.

People sometimes avoid car pools because they worry about getting stranded at work.

The Pitt ridership program offers a guaranteed-ride-home program for complications. Let’s say your boss orders you at the last minute to stay late to finish a project. People who phone the Pitt office will get cab fare or the use of a car overnight.

The Southwestern Pennsylvania Commission also offers a guaranteed-ride-home program for companies that agree to fill out a monthly report. But so far, no corporation has enrolled in that program, some preferring to pay for the employees’ cab fares themselves.

Car pools can be set up various ways. The most common arrangement, says Session, is for four people to take turns driving and paying the expenses. No money changes hands.

In other car pools, the same person drives every day. "Everyone else pays the expenses," Session said. "The driver rides for free."

Like spouses and roommates, car poolers occasionally clash.

The most common cause for a commuter breakup is that one of the riders is always running out of the house late with briefcase flying, a la Dagwood Bumstead.

"Once you are mad at someone because they have made you late for work, you think about what else is aggravating you," Imbrogno said.