Interstate 75

Interstate 75 (I-75) is a major north–south Interstate Highway in the Eastern United States, stretching from the Great Lakes to the Southeastern regions. As with most Interstates that end in a five, it is a major cross-country, north–south route, one of the longest in the U.S., from southern Florida to the northern tip of Michigan. It travels from State Road 826 (FL 826) and FL 924 on the Hialeah–Miami Lakes border (northwest of Miami, Florida) to Sault Ste. Marie, Michigan, at the Canadian-American border.

I-75 passes through six different states including Florida, Georgia, Tennessee, Kentucky, Ohio, and Michigan over its routing. The highway runs the length of the Florida peninsula from the Miami area and up the Gulf Coast through Tampa. Further north in Georgia, I-75 connects to Macon and Atlanta before running through Chattanooga and Knoxville and the Cumberland Mountains in Tennessee. I-75 crosses Kentucky, passing through Lexington before crossing the Ohio River into Cincinnati, Ohio. In the Buckeye State, the highway runs up the western side through Dayton before crossing into Michigan north of Toledo. I-75 runs northeasterly along the Lake Erie shoreline and Detroit River into the city of Detroit before turning northwesterly and northward to the Mackinac Bridge where the freeway crosses the strait between Lakes Huron and Michigan. Further north, I-75 approaches the Canadian border down river from Lake Superior, 1,786 miles (2,874 km) from its origins near the Atlantic Ocean.

Interstate 75 is the second longest north-south interstate highway following Interstate 95 and the seventh longest Interstate Highway in the system.

Route description

Florida

Main article: Interstate 75 in Florida

I-75 (unsigned State Road 93, except in the Tampa Bay area, where I-75 is State Road 93A) starts at an interchange with FL 924 and FL 826 on the Hialeah–Miami Lakes border in suburban Miami. After an intersection with the Homestead Extension of Florida's Turnpike (HEFT) and an interchange with I-595 and the Sawgrass Expressway, the Interstate leaves the Miami metropolitan area and turns westward to travel through the Everglades along the tolled Alligator Alley, which brings the highway to the Gulf Coast and Naples, where it again heads north. Passing through Bonita Springs, Fort Myers, and Sarasota, I-75 encounters a series of construction projects that will increase the lane count from two lanes in each direction to three in each direction. The freeway enters the Tampa Bay metropolitan area before the interchange with I-275 northbound, which handles St. Petersburg-bound traffic. Within the Tampa metro are three more major junctions: One with the Lee Roy Selmon Expressway which carries traffic into downtown Tampa; one with I-4 which carries traffic across the center of the state to the East Coast; and another as I-275 traffic defaults back onto northbound. The freeway proceeds to enter suburban portions of Pasco, Hernando, and Sumter counties, where it intersects the western terminus of Florida's Turnpike. Then I-75 heads northwestward on its way to Ocala and Gainesville. At Lake City, Florida, the Christopher Columbus Transcontinental Highway, I-10, intersects with I-75. Afterward, the northmost stretch of I-75 in Florida exits the Sunshine State into southern Georgia, the Peach State. I-75 in Florida is the longest section of an Interstate Highway east of the Mississippi River, with a milepost-based length of 471 miles (758 km).

Georgia

Main article: Interstate 75 in Georgia

I-75 (unsigned State Route 401 within Georgia) enters Georgia near Lake Park, and it continues northward through the towns of Valdosta, Tifton and Cordele until it reaches the Macon area, where it intersects with I-16 eastbound towards I-75's route. For northbound traffic wishing to avoid potential congestion in Macon, I-475 provides a relatively straight bypass west of that city and I-75's route. After Macon it passes the small town of Forsyth. The freeway reaches no major junctions again until in the Atlanta metropolitan area. The first metropolitan freeway met is I-675, then followed by the Atlanta "Perimeter" bypass exit 238 and 259, I-285. It crosses inside the Perimeter and heads north several miles towards the Atlanta city center. Interstate 75 then runs concurrently with I-85 due north over the Downtown Connector through the central business district of Atlanta. I-75, co-signed with I-85, also meets I-20 on exit 247. The areas where I-85 and I-75 run concurrently are some of the most traffic-prone streets in the nation because it has at least 16 lanes. After the two Interstates split, I-75 makes a beeline northwest, crossing outside the I-285 perimeter and heading towards the major suburban city of Marietta. This section of I-75 just north of I-285 has 15 through lanes. North of Marietta, the final major junction in the Atlanta metropolitan area is the I-575 spur. I-75 then traverses the hilly northwestern Georgia terrain as it travels towards Chattanooga into the Tennessee state line. All of Interstate 75 in Georgia is at least 3 lanes in each direction, except for a short segment in Macon, where I-75 is 2 lanes in each direction and I-475 is 3 lanes in each direction.

Tennessee

Main article: Interstate 75 in Tennessee

The freeway enters Tennessee directly in the Chattanooga metropolitan area, where it intersects with I-24. Exiting Chattanooga to the northeast, I-75 passes through an area known for dense fog. Twelve people were killed and 42 were injured in a 99-vehicle accident on that stretch of I-75 in heavy fog on December 11, 1990. I-75 does not meet any other freeways until it overlaps I-40 near Farragut and heads eastbound. Together, they enter the outskirts of Knoxville, where I-75 overlaps itself with a different road, this time I-640, but only for a short time. When the two meet I-275, I-75 encounters some of its highest points of elevation through the Cumberland Mountains and Cumberland Plateau region, cutting through the uppermost peaks and ridges of the mountains.

Michigan

Interstate Highway System

Major Interstates are written in bold.