A P3 is a partnership between a government agency (in this case, the Maryland Transit Administration) and a private firm (called a “concessionaire”) to build and operate an infrastructure project. Many P3s are toll roads, like the new Beltway HOT lanes in Northern Virginia. But transit P3 projects are fairly new to the United States. Currently, the only example in the nation is in Denver, which is using one to build almost 70 miles of rail projects.
