List of Interstate Highways in Utah
The Interstate Highways in Utah are maintained by the Utah Department of Transportation (UDOT). The Interstate Highway System is a nationwide system with only a small portion of these routes entering Utah. Originally, the State Road Commission of Utah, created on March 23, 1909 was responsible for maintenance, but these duties were rolled into the new UDOT in 1975. There are of Interstates within the state. The longest is Interstate 15 (I-15) at and the shortest is I-215 at . One unique former route is Interstate 415, which was never signed as such, and was only used as a temporary designation for the eastern portion of what is now the Interstate 215 belt loop around Salt Lake City.
Delaware State Route System
The Delaware State Route System includes Delaware's portion of the Interstate Highway System and U.S. Highway System along with state routes. The system also includes special routes of the U.S. and state routes, such as alternate, business, and truck routes. These routes consist of a banner denoting the type of special route above the route marker. Alternate routes provide a second alignment of a route between two points. DE 10 Alternate provides an alternate routing to DE 10 between Willow Grove and Rising Sun by passing through Woodside while DE 10 passes through Camden. Business routes pass through the business area of a city while the main route bypasses it. DE 1 Business passes through the central portion of Milford while DE 1 bypasses the city to the east. Truck routes provide an alternate route for trucks around a certain portion of a route. DE 14 Truck provides a route for truck traffic that bypasses the section of DE 14 that passes through Harrington. Suffixed routes also exist for short alignments that branch off their parent routes, in which a letter suffix is added after the route number. DE 1 has three suffixed routes in the Rehoboth Beach area while DE 9A provides access to the Port of Wilmington from DE 9. In addition to these systems are other state roads designated with a maintenance road number.
DelDOT maintains a total of of state roads within Delaware, which comprises 89 percent of all roadway mileage in the state. Some exceptions to DelDOT maintenance include the bridges over the Chesapeake and Delaware Canal, which are maintained by the U.S. Army Corps of Engineers, and the Delaware Memorial Bridge, which is maintained by the Delaware River and Bay Authority (DRBA). A total of of Delaware's roadways are part of the National Highway System, a system of highways important to the United States's economy, defense, and mobility. This system includes all the Interstate Highways in Delaware, other principal arterials which connect to intermodal transportation facilities, and the Strategic Highway Network which provides connections to major military facilities in the United States. The longest route overall in Delaware is US 13 at , with DE 1 being the longest state route at . At a length of , I-95 is the longest of Delaware's three Interstate Highways. The shortest route is DE 491 at .