The 27-mile Park Loop Road is the main route for driving to Acadia National Park’s hiking trails and natural attractions, including Cadillac Mountain, the park’s highest elevation at 1,530 feet. Automobiles were banned between 1908 and 1915, due to disagreement between Mount Desert Island’s year-round residents and summer visitors about whether to allow automobiles across the causeway. Seeing the inevitability of the automobile in the park, summer resident John D. Rockefeller, Jr. partially financed the construction of the loop road to keep cars out of the park’s interior and off the carriage roads. He hired Frederick Law Olmsted, Jr. of Olmsted Brothers in 1929 to recommend routes, locate scenic overlooks, remove native vegetation to open up views, add new native plants, and prepare engineering details for the road’s width, curvature, gradient, and speed limit. The work also involved realigning, abandoning, or closing sections of existing roads. In some areas the Park Loop Road intersects with Acadia’s historic carriage roads, passing under the carriage network’s stone bridges or intersecting at grade but kept separated by gate lodges, such as at Jordan Pond and Brown Mountain. The Park Loop Road was listed as part of the Acadia National Park Multiple Property Listing in the National Register of Historic Places in 2005.