Dec. 1 has become D-Day for the Port Authority and its bus-trolley riders.

That's when a labor contract adopted by the authority board is to be imposed upon Local 85, Amalgamated Transit Union, covering 2,200 bus-trolley workers and an associated bargaining unit covering about 100 first-level supervisors.

Dec. 1 also promises to trigger a series of events that will largely shape the future of the 44-year-old agency.

Essentially, the authority wants the union to report to work under terms of its "final and best" offer made during negotiations, one providing annual 3 percent pay raises but requiring higher employee contributions for pensions and health care.

Union leaders have claimed such a contract is illegal and would constitute a lockout. They especially don't like added provisions designed to deal with excessive absenteeism and expanding the authority's ability to contract out jobs traditionally performed by the union.

Authority officials said they acted within terms of federal law after negotiations and a fact-finding process failed. They said prospects of a settlement appeared "hopeless" and legacy obligations continue to mount beyond the agency's means as long as Local 85 keeps working under terms of the previous contract, which expired June 30.

Consequently, labor-management relations are the worst since 1992, when it took court intervention to settle a 28-day strike.

The situation has become further complicated by financial issues, including County Executive Dan Onorato's refusal to release $27.7 million being collected this year from the county's drink and car-rental taxes until the authority increases operating efficiency and reins in long-term labor costs.

The timing of labor and financial matters coming to a head couldn't be worse. Figures obtained Friday show the Port Authority averaged 247,432 rides a day last month, a 3.7 percent increase for the year, but, more significantly, the highest number of riders in many years.

Here, in question-and-answer format, are some of the issues being raised in the dispute.

Q. -- What's going to happen on Dec. 1? Will buses and trolleys be running?

A. -- Nobody knows for certain, but there's strong speculation that Local 85 members will report to work and transit will operate as scheduled -- at least for a while.

Because provisions of the imposed contract are to go into effect at 12:01 a.m., look for union attorneys to turn to the courts as soon as doors open, seeking an injunction to delay the new contract and order authority officials to continue operating under terms of the previous contract already in force since July 1.

A judge is likely to set a hearing and take action ranging from renewing negotiations under court supervision to accepting or rejecting the authority's imposed contract. If the court denies the union, some form of job action could follow -- either as a strike or a lockout, depending on points of view and legal interpretations.

If operations continue under the old contract, Mr. Onorato has vowed not to release the county's subsidy, meaning the authority's matching money from the state will be withheld as well.

That opens another Pandora's box.

Because the authority will be unable to meet payroll and expenses, it will be forced to park the buses and trolleys and close its doors indefinitely sometime next month, the status of the contract dispute notwithstanding.

The authority board is tentatively planning to announce a shutdown date Nov. 26 at its monthly meeting.

Q. -- If Mr. Onorato releases the transit tax money, won't all problems be solved?

A. -- Because of escalating costs and expectations of little additional state funds in the future, Mr. Onorato has said it would be better to shut down and resolve labor and cost issues now. Otherwise, they'll only be put off to a later day, requiring such drastic service cuts and fare hikes that Allegheny County residents will no longer be left with a viable public transit system.

Q. -- Is anything else possible between now and Dec. 1 to avert court, a strike, lockout or shutdown?

A. -- Yes. Key decision makers could meet behind closed doors and work out a deal. That's a quietly increasing possibility, because many influential people in the community want the dispute involving the union, management and Mr. Onorato to end.

If secret negotiations succeed, Mr. Onorato will release the money that he has been withholding, The state will provide its $15.3 million monthly share of aid for January, Mr. Onorato will enhance his political image, transit will have a rosier future and the uncertainty will end for riders and business.

Q. -- What do union leaders plan for the Nov. 23 membership meeting?

A. -- In a statement, Local 85 says it is holding an "informational meeting to educate members on the status of negotiations and to share legal options available to the union."

What President-Business Agent Pat McMahon said may somewhat ease anxieties about a possible work stoppage Dec. 1: "We have no intentions of voluntarily stopping work."

Q. -- Will the union vote to go on strike?

A. -- It never has. What members do, usually in a hand vote, is authorize their 20-member executive board to call a strike, if necessary, and only as a measure of last resort. Then the officers and executive board members make the final decision.

There likely would be little sympathy for the union workers because of their wages, job security and generous benefits; their employee contributions would be minor compared to "givebacks" at many places of employment in the private sector; nonunion colleagues have had wages frozen and benefits cut; and, finally, these aren't the best of economic times.

Q. -- If there is a strike or a lockout, how long will it last?

A. -- Call it a strike or call it a lockout, what matters most to riders, employers and taxpayers is that a work stoppage means the buses, trolleys and Mon Incline won't be running.

If transit service is halted for one day, officials say, it might as well last for 100 days or 200 days because the damage will have already been done. The Port Authority has yet to recoup riders and its standing from the 1992 strike, when both management and the union had to share blame.

Q. Why did fact-finding fail?

A. -- The results were somewhat of a surprise, because the state-appointed, neutral third party was said to have worked hard to make recommendations that would represent compromise and achieve a contract.

After scheduling a vote, Local 85's executive board decided to postpone it until the authority's board of directors voted.

The authority board accepted, although the contract did not come near providing the cost-savings it sought.

Later the same day, the union's board voted to reject, although it would have given members 3 percent wage increases and a far better deal in every respect than the "final and best offer" contract being imposed on Dec. 1.

The union rank-and-file never had the opportunity to vote on the fact-finder's recommended contract.

Late last week, Mr. Onorato said the union "may have left its best deal on the table," referring to the fact-finder's report. He also hinted he might still be willing to go along with it, if Local 85 changes it mind.

Q. -- How many riders would be impacted by a work stoppage?

A. -- The Port Authority now provides about 247,000 rides on a week day, including ACCESS paratransit service that wouldn't be impacted by a strike, although there would be delays attributed to increased demands for call-ahead service.

Bus-trolley ridership statistics count people who transfer, such as riding one bus Downtown and then boarding another one to reach Oakland.

Ergo, the number of people who take round trips by bus or trolley each day comes to more than 110,000, or the equivalent of almost twice as many people as those who attend Steelers games at Heinz Field.

About 45 percent of those who come Downtown on the average week day arrive by public transit, a strong number by industry standards. Ridership is comparable in Oakland, where traffic is equally congested and parking is at a premium.

A high percentage of riders are "transit dependents." That is, they have no other means of transportation, adding to the Port Authority's significance.

Q. -- What should Port Authority riders do in the meantime?

A. -- To borrow an old saying, "Prepare for the worst, hope for the best."

Many employers have come up with plans in the event of a work stoppage. The Port Authority has established a Web site, just in case, www.pghtransitinfo.com, containing items from fare reimbursement to park-n-ride lots and frequently asked questions.

Riders can stay abreast with plans and developments with the Post-Gazette and its Web site, www.post-gazette.com.

Q. -- A frequent question is this: If there's a work stoppage, will construction stop on the North Shore Connector project?

A. -- No. The project is separately funded and administered out of the Port Authority's capital budget, which is separate from its operating budget covering day-to-day operations, payroll, fuel and related expenses.

The salaries of a handful of management staffers who will remain on duty to supervise the project and continue with paperwork will be charged off to the capital budget.