How do you plan for a transportation tsunami?
Where do you park 10,000 charter buses? How do you accommodate a possible 1 1/2 million would-be riders on a subway system with a capacity of about 1 million? How do you explain to people who are used to driving everywhere that their cars aren't welcome in downtown Washington? What happens on the roads, at the airports and aboard the trains when millions of visitors flood the capital region to witness history at the Jan. 20 inauguration of Barack Obama as the 44th president of the United States?
Federal government officials and transportation agencies in Maryland, Virginia and the District of Columbia are wrestling with those questions and more in the 2 1/2 weeks that remain before the transfer of power to the first African-American to hold the presidency.
They are contemplating seemingly drastic steps to handle the influx and the security issues that go with it: Metro stations near the Mall will be closed; some highways heading into the city will be turned into bus parking lots; cars will be banned from some bridges; and commuter rail and bus lines will accept only passengers who have bought special tickets in advance.
The plans - many subject to change - are complicated by uncertainty about how many people will show up. Some initially estimated that as many as 5 million visitors would come to Washington. Others now guess that half that many will come, but Washington City Administrator Dan Tangherlini said he's still crafting his plans around the higher forecasts.
"If we start letting down our guard from a planning standpoint, we could be overwhelmed," he said.
The expected record attendance at an inauguration is expected to have an impact that extends far beyond the borders of the District of Columbia.
Maryland Transportation Secretary John D. Porcari said the event will have a "ripple effect" that will be felt along the entire Interstate 95 corridor, including the McHenry and Harbor tunnels and the Key Bridge.
Traffic in Baltimore will be affected by Obama's scheduled appearance in the city Jan. 17, as well as an influx of charter buses carrying people who couldn't find affordable rooms - or rooms at all - in Washington.
"We know that there are a lot of people staying in hotel rooms in Baltimore going to the inaugural," said Porcari, whose department has assembled a working group of about 20 high-level officials to plan for the event. He added that it is possible that additional inaugural events could be scheduled in the city.
But it is Washington that faces the most enormous challenge: how to accommodate a potential crowd in the millions lining Pennsylvania Avenue and crowding the Mall.
Perhaps the greatest unknown is whether the city's widely admired Metro subway system can get through what is expected to be its busiest day ever without melting down.
"This is probably the largest event we have ever had to plan and prepare for," said Steven Taubenkibel, spokesman for the Washington Metropolitan Area Transit Administration. "This is going to be a monumental challenge - not just for this transit agency but for the entire region."
The Metro will open at 4 a.m. Jan. 20 and will operate a rush-hour schedule for 17 straight hours - until 9 p.m. The Metro is expected to shatter its previous record of carrying 854,000 on a single day and its previous inaugural record of 811,257 for Bill Clinton's 1992 swearing-in. By contrast, President George W. Bush's first inaugural in 2001 - coming on the heels of the disputed Florida balloting - barely broke the 600,000 mark.
Taubenkibel said the Metro can carry an estimated 120,000 passengers per hour - or 960,000 riders by noon if cars are at full occupancy.
Metro is urging people who live near closer-in subway stations - say, within two miles of the Mall - to lace up a comfortable pair of shoes and walk downtown. According to Taubenkibel, many trains may be at full capacity by the time they pull into stations close to the inaugural site. Some riders may have to catch an outbound train to the end of the line to ensure that they can find a place on an inbound train.
WMATA is also urging riders not to attempt to transfer between lines at such hubs as Metro Center, Gallery Place and L'Enfant Plaza. If you reach those stations, you're close enough to walk, Taubenkibel said. Two stations, Archives/Navy Memorial and Smithsonian, will be closed for security reasons.
Even more daunting than the task of getting people there will be the job of getting them home - especially if most of them decide to head for home immediately after the public ceremonies. Metro officials are urging riders to find something to do in downtown Washington in the hours after the swearing-in rather than trying to return home immediately.
"There is simply no way we can carry all those people back at the same time," Taubenkibel said. Passengers who do rush for the nearest subway station during the time of peak traffic could find themselves waiting outside because security officials will limit the number of people on the platform.
Among the most difficult challenges for transportation officials is figuring out what to do with the invading army of charter buses - up to 10,000 by some estimates - expected to roll into the Washington region. Few will be permitted to reach the Mall itself, and many will be steered to Metro connections.
Tangherlini said Washington officials are closing the Potomac Freeway and Southeast Freeway for bus parking. Other staging areas for buses will be at Robert F. Kennedy Stadium, the former home of the Washington Redskins, and the Washington Nationals baseball stadium. Worried that the Metro might not be able to absorb a high volume of charter bus riders, District officials decided last week to open three areas near downtown - but still a healthy walk to the Mall - to charter bus parking.
For Baltimore-area visitors, the most important concession to charter buses is that parking at the Greenbelt Metro - the station that is normally most accessible from the north - will be reserved for buses. Metro officials are directing Marylanders who want to drive to the Metro to such stations as New Carrollton, Glenmont and Largo.
Virginians attempting to reach the ceremonies in private vehicles face an even greater obstacle: All but one of the Potomac River bridges into the District will be limited to bus traffic. The one that will be open is the narrow and out-of-the-way Chain Bridge.
Drivers coming in from Maryland face fewer bridge closings - the 11th Street and South Capitol Street crossings of the Anacostia River are likely to be restricted - but they could face a dizzying array of street closings, detours, security stops and parking shortages.
Tangherlini said Maryland drivers should plan on leaving their cars in Maryland unless they have parking in the city lined up. He said even side streets are likely to be taken by Washington residents and their out-of-town guests.
"Figure out where you're going to park. Figure out what you can do to ensure that space will be available to you," Tangherlini said.
John Townsend, a spokesman for AAA Mid- Atlantic, said parking garages as far from the Mall as Dupont Circle will be closed for security reasons. Garages just a little farther out are likely to charge hefty premiums and fill up fast, he said.
With the expected crowds and the potential for systems to fail, visitors to Washington are also being urged to formulate backup plans. For instance, many subway stations also have Metrobus connections. John Catoe, chief executive of WMATA, has urged riders to use buses instead of trains.
The issues facing transportation planners aren't limited to local travel. The Maryland Transit Administration has adopted a special schedule of MARC trains and commuter buses for Jan. 20, with all- reserved seating. Sales began late last month, and more than half were taken by Christmas, according to the MTA.
Officials are also gearing up for a surge in flights into Washington regional airports.
Porcari said the Maryland Aviation Administration is working to accommodate a spike in air travel - in general aviation as well as scheduled flights. He said corporate jets would have to reserve space in advance at both BWI Marshall Airport and Martin State Airport.
"It's fair to say that every inch of available ramp space will be taken," he said.
Transportation officials are walking a fine line between welcoming visitors to Washington and reminding them of the comforts of home.
"People of all ages, young and old, need to think about the crowd size that day and if they come, what their plan of action is for that day," Taubenkibel said.
AAA's Townsend was more blunt. He said he was in New York during the Sept. 11 attacks, and he expects the traffic leaving Washington on Inauguration Day to be reminiscent of the exodus from Lower Manhattan on that day in 2001.
Townsend warned that few inaugural visitors will be able to attend both the swearing-in ceremony and the Inaugural Parade because of the sheer difficulty of walking from place to place.
"You have to make a decision beforehand. You have to decide which of the two you want to do," he said. "The crowds will be so massive it will be impossible to do [both]."
Tangherlini noted that the parade route will accommodate only about 350,000 people - most with tickets. Access to the Mall will be mostly from the south and from west of 18th Street N.W., though the city is looking for a way to get riders coming to Union Station across the parade route to the Mall.
"You're going to have to walk a fair amount no matter how you get here - unless you're one of the privileged few who gets to use a helicopter," Tangherlini said.
The city administrator said the big wild card in how the day goes will be the weather. "My biggest concern, frankly, is ice," he said.
Tangherlini expressed cautious optimism that the day will go well, noting that Washington's public safety officials have a unique level of experience in dealing with such gatherings.
"If anyone can handle it, these guys can," he said. "We're very excited about this event. We're going to do everything we can to make it great."
* MARC train tickets are still available from the Maryland Transit Administration but are selling fast. The $25 round-trip tickets can be bought through the MTA Web site at www.CommuterDirect.com. Some trains are sold out.
* MTA commuter buses will depart Kent Island, Annapolis, Columbia, Scaggsville-Burtonsville, Frederick, Upper Marlboro and three Southern Maryland locations the morning of Jan. 20 and connect with the Washington Metro. Tickets can be purchased onboard. Reservations are not required. Round-trip tickets are $10. Exact change is required. Schedules and other specific information can be found at www.mtamaryland.com.
* Because of potentially long lines at ticket-vending machines, riders of the Washington Metro are being urged to buy day passes or SmartTrip cards (needed to pay for parking) before Jan. 20. Commuter bus riders and other out-of-town customers can purchase tickets and cards at www.wmata.com/fares/purchase/store/.
* Plan carefully which Metro stops to use based on where you expect to be. For the parade route, use such stations as Union Station, Judiciary Square, Gallery Place and Metro Center. For the Mall, access may be easier from L'Enfant Plaza, Farragut North or Farragut West. Smithsonian and Archives/ Navy Memorial stations will be closed.
* People expecting to arrive aboard charter, church or school buses should make sure the operators have registered their vehicles with District of Columbia officials to ensure a place to discharge passengers and park. Bus operators can get passes and parking spaces by going to www.bus.dc.gov.
* Visitors who decide to park their cars and take a Metrobus into Washington can plot out their trips by visiting the WMATA Web site and using its trip planner. The buses will be operating on a modified Saturday schedule, so most routes to outer suburbs such as Bowie and Odenton will not be running. When using the trip planner be sure to set the date for Jan. 20, 2009.
* Traffic in Washington is expected to be extremely heavy and parking may be scarce. Visitors are being encouraged to use mass transit and to leave early in the morning and late in the evening.
* No passenger vehicles will be permitted to park at the Greenbelt Metro station, which is reserved for charter buses. Visitors from Baltimore may be able to find parking at such stations as Glenmont and Wheaton on the Red Line, New Carrollton on the Orange Line and Largo Town Center on the Blue Line. Parking is also expected to be available at FedEx Field near Largo.
* For return trips, walking to a station farther up the line could increase chances of catching a train before it fills. For instance, Red Line riders heading for Glenmont might want to walk to Dupont Circle. Orange Line riders heading for New Carrollton could board at Foggy Bottom. Green Line riders to Beltsville could walk to the Waterfront station at 4th and M streets S.W.
* Motorists traveling to points south of Washington during the inaugural weekend should avoid the Capital Beltway and instead use such roads as U.S. 301 through Southern Maryland or Interstate 81 through the Shenandoah Valley.
* Travelers heading to the Northeast late Jan. 20 and on Jan. 21 are advised to find alternatives to the Interstate 95 corridor, such as Interstate 83 to York or Harrisburg in Pennsylvania. Travelers to the Philadelphia area may encounter lighter traffic on U.S. 1. Potential backups at the Delaware Toll Plaza can be avoided by taking U.S. 40.
* For travel crossing Baltimore harbor, backups are less likely on the Francis Scott Key Bridge than at the Fort McHenry and Harbor tunnels.