Pope Francis waves to the faithful as he arrives in St. Peter’s square for his weekly audience on December 4, 2013 in Vatican City. (Photo by Franco Origlia/Getty Images/Getty Images)

Drivers heading into the District during Pope Francis’s visit Sept. 22-24 need to be prepared for major detours, closures and delays, D.C. officials said Thursday.

For example, a good stretch of Massachusetts Avenue in upper Northwest will remain closed during the duration of the pope’s visit.

“We are preparing for large crowds, road closures, and extensive traffic detours,” D.C. Department of Transportation Director Leif Dormsjo said Thursday. “You really do need to plan ahead because these road closures will be long in duration and they will impact some significant arterial streets.”

D.C. Transportation officials unveiled only highlights of the road closures expected during the papal visit, but they warned that as many as 70 intersections in the city will be significantly impacted due to closures and detours.  Dormsjo said there will be extensive signage in place and DDOT and National Guard personnel will be at intersections to help with vehicular and pedestrian traffic flow. The number of workers on road management efforts will be twice what is available on July 4th, he said.

Transportation officials said commuters should take Metro if they need to come into to the District, warning that the traffic disruptions are likely to frustrate travelers.

[Metro will run near rush-hour rail service during Pope Francis’s visit, but expect crowds and delays]

These are the significant road closures:

For the duration of the trip – Tuesday, Sept. 22 to Thursday Sept. 24

At the pope’s residency near the Naval Observatory:

  • Northbound lanes of Massachusetts Avenue NW will be closed to traffic from Waterside Drive NW to Garfield St. NW
  • Southbound lanes of Massachusetts Avenue will remain open.

Wednesday, Sept. 23 events

Near the White House where the pope is scheduled to meet President Obama at 9:15 a.m. and then participate in a popemobile parade around the Ellipse. The following roads will be closed starting around 9 p.m. Tuesday, Sept. 22 until 12 p.m. Wednesday, Sept. 23:

  • 14th Street between Pennsylvania and Independence avenues NW
  • Constitution Avenue between 23rd Street and 12th Street NW
  • Henry Bacon Drive NW between Constitution Avenue and Lincoln Memorial Circle NW (no access to Constitution Avenue)

Near the Basilica of the National Shrine of the Immaculate Conception where the pope will celebrate an outdoor Mass during which he will canonize Junípero Serra, an 18th-century Franciscan friar who founded missions in California. The following roads will be closed to vehicular traffic from 12 a.m. to 8 p.m.:

  • Michigan Avenue will be closed from Irving Street NE to 10th Street NE.
  • East Bound Irving Street will not allow drivers to access Michigan Avenue.

Thursday, Sept. 24 events:

At the U.S. Capitol, Pope Francis will address a joint session of Congress just after 9 a.m., and he is expected to to make an appearance on the Capitol’s West Front. Thousands of people are expected to be there to see the pope. The following roads will be closed from 12 a.m. to 12 p.m.:

  • Independence Avenue from 2nd Street SW to 3rd Street SE
  • Constitution Avenue from 3rd Street NE to 2nd Street NW

Transportation officials warn that the road closures will impact transit and the local roadway network.  Travelers should also expect parking restrictions near the events and near the Vatican Embassy.  Metro interim General Manager Jack Requa said that as many as 70 Metrobus routes will be affected.  Metro and D.C. officials are expected to release more details about the detours Monday.

Dormsjo said the bottom line is that commuters who need to come to downtown during those two days, should use public transit.

“While there will be delays associated with the intense demand for transit…transit is still the best mode of transportation to get into the downtown,” Dormsjo said, noting also other events, including a Nationals vs. Orioles game and concerts at the Verizon Center.  “If there is flexibility with those workers to telecommute, this will be a good week to do so.”