Visitors walking along M Street in southwest Washington, D.C. will mostly note an upscale, developing business neighborhood near Nationals Park—until they come face-to-face with a series of anachronisms from America’s past. It can be a bit confusing to find a 19th-century rail trolley at a busy intersection or share sidewalk seating with an eight-foot red channel marker, until one realizes the perimeter of the U.S. Department of Transportation is an outdoor museum of North American transportation.

The Transportation Walk is part of the U.S. Department of Transportation outreach to the public, with a focus on North America’s transportation evolution from the earliest efforts of Indigenous peoples through the present. Artifacts, interpretive panels, plaques, and sidewalk pavers briefly summarize and describe milestones in transportation that shaped the growth of transportation on the continent.

The entire walk takes one around the perimeter of DoT headquarters, with an exhibit every few steps. Many are full-scale artifacts from ships, barges, rail cars, and aircraft, and are usually accompanied by interpretive signs explaining their significance. Etched pavers in the sidewalk mark significant milestones in transportation. Infographic panels give illustrative summaries of historic efforts, such as the Pony Express, the construction of the Erie Canal, the role of Black Americans in railroad expansion, and the development of the Interstate Highway System.

The free-standing artifacts, placed simply on the sidewalk, give the exhibition a somewhat surreal quality. One can find a wagon wheel, an airport runway marker, and a railroad crossing signal all within a few steps of one another on M Street. The south side of the Transportation Walk is a pedestrian walkway with artifacts that include gasoline pumps from the 1950s, aircraft landing gears, and pipeline expansions valves. Picnic tables are scattered throughout, getting steady use from the lunch crowd during the workweek.

The exhibit design integrates well into the architecture of the DoT headquarters and the surrounding buildings. Exhibits and signage are often indistinguishable from one another. Some exhibits, such as three travel posters from the 1930s—40s, are displayed on buildings that are off the Walk but in plain sight. A seasonal fountain is decorated with transportation motifs.