In the state of Maine, the Maine Department of Transportation (MaineDOT) has a system of numbered highways, defined by the as "connected main highways throughout the state which primarily serve arterial or through traffic." As of 2006, 22,236 miles[1] of roadway are included in the highway system, including Interstate highways, U.S. Routes, state highways, and other urban and rural local roads.
Maine has one primary Interstate highway, I-95, within its borders, as well as four of its spurs: I-195, I-295, I-395, and I-495 (which is unsigned). All Interstate highways in Maine are part of the National Highway System and, as such, receive some degree of federal funding. All of these highways are freeways and are built under set standards for roadway design.
U.S. Route 1 has a bypass and business route, as well as several U.S. Route 1A alternates, one of which has its own (unsigned) business route as well. US-1 also has a "child" route, the intrastate U.S. Route 201, a spur route north to the Canadian border which also has its own alternate, U.S. Route 201A.
These routes are generally maintained and funded in the same manner as state routes, with these responsibilities falling to the MaineDOT.
State Routes
Maine 22 intersection on Maine 77
State routes in Maine are numbered and signed by the state, and by extension are also generally maintained and funded by the state, except in areas designated as "urban compact areas," defined by MaineDOT as "those in which the population according to the last United States census exceeds 7,500 inhabitants. Urban compact municipalities are also those in which the population according to the last United States census is less than 7,500 inhabitants but more than 2,499 inhabitants, and in which the ratio of people whose place of employment is in a given municipality to employed people residing in that same municipality according to the last United States census is 1.0 or greater." In this case, the section of road is the responsibility of the municipality.
State-aid highways
State-aid highways are roads chosen by the local municipality which serve as links between other state routes. Winter snow removal is the responsibility of the municipality, while other maintenance and funding is handled by the state, with the exception of urban compact areas.
Townways
Townways in Maine are classified as all highways that do not fall into one of the preceding categories. These roads are chosen, funded, and maintained by the towns, or the county in unorganized areas. The vast majority of highways in the state fall under this category. These also represent the closest thing to county roads in the state, as Maine does not have signed county roads as other states such as New York do.
Signage practices
State Routes
Maine's current state highway shield is a simple black-numeral-on-white-box design, identical to Massachusetts' state route shield design. Square shields are used for one- and two- digit routes, and elongated shields are used for three-digit routes and their alternate routes. Maine has three business state routes, Route 25 Business, indicated by a 'Business' shield complementing the Route 25 shield; Route Business 15 through Bangor and Brewer; and Route Business 137 through Waterville. Maine also has one truck route, Route 228 Truck, which is indicated by a 'Truck' shield complementing the Route 228 shield.
U.S. Highways
Maine uses standard shields for U.S. Routes, a white six-point shield on a black border. Square shields are used for U.S. Routes 1, 1A, 2, and 2A, while elongated shields are used for U.S. Routes 201, 201A, 202, and 302. Maine also has two business U.S. Routes, indicated by banners complementing the corresponding route shields. Maine also has a U.S. Route 1 Bypass, indicated in the same way, with a bypass shield.
Interstate Highways
Maine uses standard-size Interstate shields on its Interstate Highways. Many of Maine's Interstate shields contain the state name, and others do not. I-95 shields on the Maine Turnpike are generally accompanied by Maine Turnpike shields. The Falmouth Spur, designated I-495 in 2004, is unsigned.