Florida State Road 112

State Road 112 (SR 112) is a 9.9-mile-long (15.9 km) east–west state highway connecting Miami International Airport in Miami to Miami Beach in the U.S. state of Florida. Between the airport and Interstate 95, it is locally known as the Airport Expressway (or the Airport Tollway), and is a controlled-access toll road between SR 9 and I-95. Between I-95 and Alton Road (SR 907A) in Miami Beach, SR 112 is signed only as Interstate 195 as it crosses Biscayne Bay by way of the Julia Tuttle Causeway. Between I-195 and its eastern terminus at Collins Avenue (SR A1A), the SR 112 signs are present but infrequent, and the road is locally maintained as Arthur Godfrey Road.

Since the state of Florida renumbered its Florida State Roads in 1945, a grid system of designation was imposed. While Miami is in a region of Florida in which all three-digit State Roads should begin with an "8" or a "9", its collection of State Roads has a few that begin with a "1" (usually used south of the Georgia state line and near Gainesville and Flagler Beach, both over 300 miles (480 km) away).

SR 112 begins at the main entrance of Miami International Airport, at the intersection of NW 21st Street and State Road 953 (Le Jeune Road), and heads north. From here until the interchange with I-95, the road is known as the Airport Expressway and is maintained by the Greater Miami Expressway Agency (GMX). For its first mile or so, the road runs parallel to SR 953 and an airport runway, with its lanes featuring a divided left-hand driving direction. About 0.5 miles (0.80 km) north of the southern terminus, SR 112 features an at-grade railroad crossing, near the eastern end of one of the airport's runways. The road swings to its main east-west orientation past the airport, with its lanes crossing to a normal driving direction just to the east of its partial interchange with SR 948, which also provides limited access to U.S. Route 27.

After crossing NW 37th Avenue, the Airport Expressway passes through its first of two toll gantries, charging $0.35 for vehicles with SunPass transponders and $0.70 for the remaining Toll-by-Plate users. It also runs roughly parallel to the Metrorail Orange Line, crossing under it just west of NW 32nd Avenue. SR 112 then interchanges with SR 9 (NW 27th Avenue), and then NW 22nd Avenue half a mile later. From here, the expressway passes through the second toll gantry (at the location of the former toll plaza), charging the same rates as the first gantry. Near this gantry, SR 112 passes the southern side of the Earlington Heights Metrorail station, where the two lines of the Metrorail system merge, with both the Airport Expressway and the Metro continuing to run parallel eastwards for another 1 mile (1.61 km) or so. Just before SR 112's partial interchange with SR 933 (NW 12th Avenue), the Metrorail tracks cross over the Airport Expressway as they curve southwards. About 0.5 miles (0.80 km) later, the Airport Expressway ends at the stack interchange with I-95 (alternatively known as the 36th Street Interchange), with SR 112 and the pavement continuing eastwards as Interstate 195.

The 4.424-mile-long (7.120 km) section of SR 112 connecting Interstate 95 in the west with Miami Beach in the east is also designated as I-195. This portion of the route is signed as I-195, with SR 112 becoming an unsigned highway. I-195 and SR 112 cross Biscayne Bay by way of the Julia Tuttle Causeway. At SR 907A (Alton Road), I-195 terminates while SR 112 continues east as Arthur Godfrey Road.

East of Alton Road, SR 112 continues as the palm-lined Arthur Godfrey Road (also known as West 41st Street), a 0.82-mile-long (1.32 km) four-lane surface road. It passes through the southern end of Nautilus, past shops and low-rise office buildings, crossing the Biscayne Waterway before passing along the southern edge of North Beach Elementary School. Continuing past more shops and a hotel, SR 112 crosses the Intracoastal Waterway before immediately meeting the southbound half of SR A1A. Past here, the road becomes one lane in each direction and meets the northbound half of SR A1A one block later, terminating amidst the high-rises of Mid-Beach. 41st Street continues on a short distance into a cul-de-sac.

Tolls on the Airport Expressway are all electronic, meaning there are no cash transactions. Payment is done either via SunPass transponders or via toll-by-plate billing, the latter of which charges double of the former. Two toll gantries are located along the expressway portion of the road, each charging $0.35 for SunPass users and $0.70 for Toll-by-Plate. As of November 15, 2014, it costs $0.70 to travel the entire expressway portion via SunPass (and $1.40 via Toll-by-Plate). All motorists are charged at least one toll for using the road; there are no "free sections" as existed prior to the electronic toll conversion in 2014.

Construction of SR 112 began in 1959, and the expressway was opened to traffic on December 23, 1961 (six months after the Palmetto Expressway, SR 826). Its initial name was the 36th Street Tollway, but use of the name eventually faded in favor of the more popular "Airport Expressway". Initially the toll road had its western terminus at the congested intersection with LeJeune Road (SR 953), Northwest 36th Street (SR  48), and Okeechobee Road (US 27 / SR 25) just east of the airport. It wasn't until 1990 when SR 112 was extended southward and westward onto the airport property, terminating at the main entrance.^{[citation needed]}