Interstate 75 (I-75) is a part of the Interstate Highway System that runs from the Hialeah–Miami Lakes line to the Canada–United States border at Sault Ste. Marie. I-75 begins its national northward journey near Miami, running along the western parts of the Miami metropolitan area before traveling westward across Alligator Alley (also known as Everglades Parkway Excerpted in ), resuming its northward direction in Naples, running along Florida's Gulf Coast, and passing the cities of Fort Myers, Punta Gorda, Venice, and Sarasota. The freeway passes through the Tampa Bay area before turning inward toward Ocala, Gainesville, and Lake City before leaving the state and entering Georgia. I-75 runs for in Florida, making it the longest Interstate in the state and also the longest in any state east of the Mississippi River.
The portion of I-75 from Tampa northward was a part of the original 1955 Interstate Highway plans, with I-75's southern terminus at I-4's current western terminus. Planning to extend the Interstate south to Miami began in 1968 after massive growth in Southwest Florida, which resulted in I-75 being realigned to travel on the eastern fringes of the Tampa Bay area, and the last portion of the highway was opened in 1993.
For Florida Department of Transportation (FDOT) inventory purposes, it is designated as State Road 93 (SR 93) for most of its length in Florida (with exception to the Tampa Bay area, where SR 93 follows I-275, while SR 93A travels with I-75 in the latter's bypass of the area).
Route description , I-75 in Florida is long. The speed limit is throughout the state. The Florida Legislature authorizes FDOT to establish speed limits on Interstates and state highways.
South Florida
I-75 begins its northward journey at an interchange with SR 826 (Palmetto Expressway) and SR 924 (Gratigny Parkway) on the Hialeah–Miami Lakes border, near Miami.
As it curves around the border of Miami Lakes, I-75 serves some of the western fringes of South Florida as an eight-lane highway. After an exit with SR 860, I-75 has an interchange with the Homestead Extension of Florida's Turnpike before crossing into Broward County. There, it continues through the western suburbs of Pembroke Pines, Weston, Miramar, Davie, and Southwest Ranches.
At the junction of SR 869 (Sawgrass Expressway) and I-595, I-75 (while maintaining its south–north status) enters a west–east trajectory as it crosses the Everglades by way of Alligator Alley, a toll road that runs from the Collier Boulevard (exit 101) toll plaza to the U.S. Highway 27 (US 27) toll plaza (exit 23). It was originally constructed as a two-lane highway before it was converted to a four-lane highway meeting Interstate Highway standards. At this point, I-75 loses a lane in each direction, heading west, losing another lane west of the US 27 interchange.
The Everglades and Southwest Florida
The Alligator Alley section of I-75 runs due east–west between exit 19 in Sunrise and exit 101 just east of Naples and is one of only two sections along the Interstate's entirety that is tolled (the other is the Mackinac Bridge in northern Michigan). Tolls are $3.75 for a two-axle vehicle as of July 1, 2023, and are collected in both directions. The highway's toll plazas accept both cash and transponders in the SunPass network and are located at either entrance to Alligator Alley. The toll facilities along Alligator Alley and toll revenue collected from them are overseen by Florida's Turnpike Enterprise (FTE). There are two interchanges along the tolled portion of Alligator Alley in addition to three rest areas and a number of scenic outlook points as the highway crosses the Everglades. I-75 enters Collier County along Alligator Alley just west of the Snake Road exit (exit 49) and passes through the Big Cypress National Preserve between the Collier County border and SR 29 (exit 80). Several small bridges along Alligator Alley allow wildlife to pass safely under the freeway, especially along the Florida Panther National Wildlife Refuge east of SR 29. Extensive fencing also prevents wildlife from interfering with traffic.
As it approaches Naples at County Road 951 (CR 951; exit 101), Alligator Alley ends. The Interstate is toll-free for the rest of its length in Florida and makes a sharp turn north, resuming its north–south trajectory, and as it parallels Florida's west coast, it becomes six lanes. As it continues north, I-75 passes near Bonita Springs, Fort Myers, Punta Gorda, Port Charlotte, Venice, Sarasota, and Bradenton before reaching the Tampa Bay area metropolis consisting of Tampa and St. Petersburg.
Tampa Bay area
North of Ellenton, I-275 splits from I-75 to serve St. Petersburg and Pinellas County via the Sunshine Skyway Bridge and Tampa via the Howard Frankland Bridge. I-75 parallels the eastern shore of Tampa Bay as a bypass route of the Tampa Bay area, as it passes by the communities of Brandon, Temple Terrace, and New Tampa. Two expressways access Downtown Tampa from I-75: the Lee Roy Selmon Expressway (SR 618) and I-4. Within the Tampa Bay metropolitan area, many interchanges are far more complex than mere diamond, cloverleaf, or even single-point urban interchanges. Aside from the large turbine interchange with I-4 (exit 261), there are interchanges with SR 582 (Fowler Avenue; exit 265) and SR 579 (Fletcher Avenue/Morris Bridge Road; exit 266) that contain both loops and flyovers. A flyover ramp was built from southbound SR 581 (Bruce B. Downs Boulevard; exit 270) to southbound I-75.
Northern Florida
At the Hillsborough–Pasco county line (south of SR 56 [exit 275]), I-275 rejoins I-75 (at exit 274, southbound only) and I-75 changes into a southwest–northeast trajectory as it passes through Pasco, Hernando, and Sumter counties where it runs through parts of the Withlacoochee State Forest on its way to the junction with Florida's Turnpike (exit 328, accessible from southbound I-75 only [although northbound travelers can access the Turnpike from I-75's exit 329 and follow SR 44 to the Turnpike's exit 304]). Widened median segments exist in northern Pasco, Hernando, and Sumter counties north of CR 476B (exit 309). Some of these median segments are actually considered part of the Withlacoochee State Forest itself. The Withlacoochee State Trail runs beneath I-75 between US 98/SR 50 (exit 301) and the Hernando–Sumter county line, where it also crosses over the Withlacoochee River. All of I-75 from the Georgia border to Tampa is three lanes in each direction, unless closed for construction. This is to accommodate for the immense number of tourists and vacationers that come to Florida.
After Florida's Turnpike, I-75 changes into a general southeast–northwest trajectory, which is sustained to the Georgia state line and beyond. I-75 passes beneath the Cross Florida Greenway, which contains a land bridge built across the highway in 2001 between exits 341 and 350, before entering the city of Ocala, and passing by the cities of Gainesville and Lake City and crosses I-10 at an interchange before entering the state of Georgia, near Valdosta.
I-75 runs closest to US 41 except between Tampa and High Springs. It runs closer to US 301 between Ellenton and Temple Terrace, and again from Dade City to Sparr. From Belleview to Lake City, it runs closest to US 441.
History
Original route to Tampa Original plans for I-75 called for its southern terminus to be in Tampa, where it would terminate at I-4 (at the current interchange between I-4 and I-275, with I-4, which was completed in the Tampa Bay area by 1962, continuing west along what is now I-275 over the Howard Frankland Bridge into St. Petersburg). Plans for I-75 from Tampa to Sault Ste. Marie, Michigan, were authorized as part of the Federal-Aid Highway Act of 1956, signed into law by President Dwight D. Eisenhower, which created the Interstate Highway System.
Construction of the original route from the Georgia border to Tampa via Gainesville and Ocala lasted through most of the 1960s. The first segment of I-75 to open in Florida was from the Georgia border to SR 6 just south of Jennings, which opened in 1963. It would reach US 90 in Lake City later that year. By mid-1964, I-75 opened from Lake City to the newly completed Florida's Turnpike (known then as the Sunshine State Parkway) in Wildwood. Segments of the original route that are now part of I-275 near Tampa would begin opening in 1966, and construction of the full route would be completed by 1969.
Extension to Miami Due to major growth in Southwest Florida (particularly Fort Myers and Naples), it was becoming clear that this part of the state would soon need a freeway. Florida's state government first proposed to build a West Coast Turnpike in 1964 from the Tampa Bay area south to Naples. Plans for the West Coast Turnpike (which would have been tolled) were canceled in 1968, when it was announced that US Secretary of Transportation Alan S. Boyd had approved an extension of I-75 south to Naples and then east to Miami. The federal government would pay for 90 percent of the extension using funds allocated by the Federal-Aid Highway Act of 1968, which was signed into law by President Lyndon B. Johnson.
In preparation for the extension, I-75's designation was extended along the preexisting route of I-4 over the Howard Frankland Bridge into St. Petersburg by the end of 1969 (I-4's designation would be truncated to its current terminus at this time). From St. Petersburg, I-75 was proposed to continue south over the Sunshine Skyway Bridge and continue south along a new freeway roughly parallel to the Tamiami Trail (US 41) along the lower Gulf Coast to Naples.
As the extension was planned in 1968, plans were also made for a freeway bypassing Tampa Bay to the east. The bypass was initially planned to be designated Interstate 75E (I-75E), and was to split from I-75 near Wesley Chapel and rejoin it just north of Ellenton. However, in 1972, it was determined that maintaining the main route of I-75 through Downtown Tampa would eventually require major improvements to the existing infrastructure to handle through traffic. Additionally, neither the 1954 nor 1971 spans of the original Sunshine Skyway Bridge were up to Interstate Highway standards as they both lacked shoulders. As a result, it was decided that I-75 would be re-routed and instead follow the bypass route. FDOT could have renumbered I-75E into what could have possibly been Interstate 75W (I-75W), but, due to a 1973-based American Association of State Highway and Transportation Officials (AASHTO) rule indicating that suffixed routes were to be renumbered to reduce motorist confusion, the option of renumbering I-75E into I-75W was scrapped, with the I-75E designation instead being renumbered to what is known today as I-275, and both the I-75 and I-275 designations were swapped into their current configuration in 1973. I-75 reached as far south as 38th Avenue North in St. Petersburg when the designations were switched. Despite the designation switch, both freeways' hidden designations still reflect the originally planned routing, with I-75's SR 93 designation following I-275, and the current route of I-75 on the bypass being designated SR 93A. Construction on the bypass segment of I-75 began in 1979.