such as trucks, are prohibited from the George Washington Memorial Parkway. However, taxicabs and airport shuttles are allowed to operate on the parkway. Northern section The northern section extends from North Washington Street at First Street, at the northern end of Old Town Alexandria, to its terminus at Interstate 495 (I-495, Capital Beltway), in Fairfax County, just south of the Potomac River. It follows the Potomac River, passing through Arlington County, and serves as the primary access point to Ronald Reagan Washington National Airport. The Parkway also provides automobile access to Theodore Roosevelt Island, the LBJ National Grove, Gravelly Point Park, Fort Marcy, Columbia Island Marina and Turkey Run Park. There are scenic view rest areas for those wishing to view the Georgetown skyline and the Potomac Palisades. The cloverleaf interchange with the 14th Street Bridge, dating to 1932, is one of the oldest cloverleaf interchanges in the United States. The Spout Run Parkway connects the George Washington Memorial Parkway to US Route 29 (US 29), providing an indirect connection to I-66. The portion of the parkway north of National Airport and SR 233 is part of the National Highway System. History Early efforts to build a road The trip by DC area residents to see George Washington's family estate at Mount Vernon was seen in the late 19th and early 20th centuries as a patriotic duty as well as an opportunity to learn about American history and democratic values. In the late 19th century, most people took a steamboat excursion from DC (it also made a stop in Alexandria). By the 1920s, 200,000 people a year were visiting Mount Vernon. In the 1880s, officials in Alexandria, Virginia, attempted to boost local commerce by advocating for a "national road" to Mount Vernon. They formed the Mount Vernon Avenue Association in September 1887, to promote this idea. Congress appropriated $10,000 for a survey in 1889. The United States Army Corps of Engineers conducted the survey, and in its report agreed that a superior, no-expense-spared road from Alexandria to Mount Vernon was necessary. However, construction of the Washington, Alexandria, and Mount Vernon Railway (an inexpensive commuter trolley/streetcar system) between 1892 and 1896 dealt a serious blow to the plan. During the Alexandria Sesquicentennial in 1899, several Alexandria civic boosters called for a bridge to be built between Alexandria and Washington, DC. This reignited interest in a roadway to Mount Vernon. The idea