Pennsylvania Avenue lighthearted celebrations, including a series of day- and nighttime Shriner's parades in the 1920s and 1930s. Thomas and Concepcion Picciotto are the founders of the White House Peace Vigil, the longest running anti-nuclear peace vigil in the US, at Lafayette Square on the 1600 block of Pennsylvania Avenue. After the Oklahoma City bombing in 1995, the Secret Service closed the portion of Pennsylvania Avenue in front of the White House to all vehicular traffic. Pedestrian and bicycle traffic, however, was still permitted on the sidewalk. After 9/11 this policy was made permanent. Near the White House traffic is redirected to
Pennsylvania Avenue trialed on the avenue: cobblestones in 1849 followed by Belgian blocks and then, in 1871, wooden blocks. In 1876, as part of an initiative begun by President Ulysses S. Grant to see Washington City's streets improved, Pennsylvania Avenue was paved with asphalt by Civil War veteran William Averell using Trinidad lake asphalt. On September 30, 1965, portions of the avenue and surrounding area were designated the Pennsylvania Avenue National Historic Site. The National Park Service administers this area which includes the United States Navy Memorial, Old Post Office Tower, and Pershing Park. Congress created the Pennsylvania Avenue Development Corporation (PADC)