The state manages the highway network through the Alabama Department of Transportation, abbreviated ALDOT.
The state of Alabama is a major hub of several Interstate Highways , more so than neighboring Mississippi. Interstate 10 passes through the south of the state, parallel to the Gulf of Mexico, through the port city of Mobile. Interstate 20 runs east-west through the center of the state through the largest city of Birmingham and is double -numbered to the west with Interstate 59. Both routes split, with I-20 running east to Atlanta, while I-59 running northeast to Chattanooga. Interstate 22 is an east-west route in the northwest of the state, from Memphis to Birmingham. The Interstate 65 is the state’s primary north-south route, running from Mobile through Montgomery and Birmingham to the border with Tennessee, with Interstate 565 branching off to the northern city of Huntsville.
Interstate 85 begins in Montgomery and then heads northeast to the Georgia border toward Atlanta. The main flows of through traffic run east-west or diagonally through the state, for example, the combination I-10, I-65 and I-85 is commonly used between New Orleans and Atlanta. The combination of I-22 and I-20 is used for traffic from Memphis and west to Atlanta.
Various short auxiliary routes of the Interstate Highways complement the network at the larger cities. Interstate 165 is a spur in Mobile, while Interstate 359 forms in the western city of Tuscaloosa. Interstate 459 forms Birmingham ‘s southern and eastern bypass, and Interstate 759 is a spur in the eastern city of Gadsden. The main places not served by Interstate Highways are Dothan in the southeast and Florence-Sheffield in the northwest.
- Bittranslators: State overview of Alabama, including geography, economy, population and history as well as introduction to major cities of Alabama.
A reasonable number of US Highways cross the state. Before the construction of the Interstate Highways, these were the main thoroughfares, but with the completion of the Interstate Highway network, many routes fulfill a secondary importance to the Interstates. US 43 is a major north-south route in the western half of the state that is largely without an Interstate Highway. This runs from Mobile via Tuscaloosa and Florence to the border with Tennessee. US 45 runs northwest from Mobile to Mississippi and US 72 is a major east-west route in the north of the state, passing through Florence and Huntsville.
US 80 forms a major east-west connection through the center of the state and is considered the major missing link of an Interstate Highway between Meridian, Mississippi, and Montgomery. The US 82 forms the connection between Montgomery and Tuscaloosa, among other things. The US 231 is, among other things, the connection from Dothan to Montgomery. US 280 connects Birmingham to Columbus, Georgia. US 431 is the longest north-south route in the east of the state.
Most US Highways that do not run parallel to Interstate Highways are designed as 2×2 divided highway. Thus, fast and safe traffic is still possible in regions where there are no Interstate Highways. The secondary road network is therefore well developed in Alabama.
- Deluxesurveillance: Nickname of Alabama as The Yellowhammer State. Also covers geography, history, economy, politics and administration of the state.
The secondary road network is formed by state routes. Even numbers run east-west and odd numbers run north-south, in addition, US Highway numbers are not re-used for state routes. State routes have single-digit, two-digit, or three-digit numbers, but few numbers above 300 are assigned. Some state routes are partially or completely unsigned, especially when they intersect with US Highways.
The longest state route, State Route 3, is 603 kilometers long, but completely coincides with US 31 and is therefore not signposted at all. The longest state route that is signposted is State Route 69 which runs for 452 kilometers from Jackson to Guntersville. State routes do not always follow logical routes or the fastest routes between start and end. They are usually not driven over great distances by through traffic.
Alabama has several toll roads. None of these is a major route.
- Foley Beach Expressway: Toll road between I-10 and Gulf Shores southeast of Mobile.
- Joe Mallisham Parkway: Toll road on the west side of Tuscaloosa.
- Emerald Mountain Expressway: Toll road just outside Montgomery.
- Montgomery Expressway: Toll road between Montgomery and Prattville.
In the early days of the automobile era, Alabama already had a sizeable population of over 2 million residents. In 1900 Mobile, Montgomery and Birmingham were all about the same size with about 35,000 inhabitants. From 1910 Birmingham became the dominant city of the state, growing to more than 130,000 inhabitants in 10 years and almost 180,000 in 1920.
From the 1920s onwards, the road network began to be asphalted on a systematic scale. In the early years the road network was characterized by little hierarchy, there were no clear main roads in the 1920s, although the Birmingham to Montgomery road in 1926 was the state’s first longer tarmac road. Also, the road from Birmingham via Gadsden to the Tennessee River at Guntersville was a longer tarmac road. Elsewhere there were scattered gravel roads and often also dirt roads. In 1926 the road from Mobile to Montgomery was still partly a dirt road, which was problematic because Alabama receives a lot of precipitation and these roads quickly became impassable. By 1930 almost all roads of any importance had been upgraded to gravel roads.
US Highways were introduced in 1926. Many routes, however, were still unpaved in 1930, not even between the largest cities. However, from 1926 clear priority was given to the US Highways, which gave the poorly organized network of ‘roads’ a better hierarchy, in the 1930s mainly the US Highways were asphalted. By 1938, most US Highways were paved, with the exception of southwestern Alabama, the area north of Mobile had no paved roads other than US 31. Shortly after World War II, southern Alabama in particular caught up, and by 1950 nearly all roads of any through importance had been paved.
Beginning in the 1950s, the first US Highways were widened to 2×2 lanes, initially rather short sections as approach roads to the larger cities. On December 10, 1959, the first stretch of freeway in Alabama, Interstate 65., opened around Warrior, north of Birmingham. During the 1960s, work was done on the various Interstate Highways in the state. Several longer stretches were completed by 1970, the longest being I-59 from Birmingham to the Georgia border and I-65 between Mobile and Montgomery. However, the completion of the Interstate Highways took a relatively long time, as the last missing links of I-20 and I-65 were only opened in the early 1980s. In 1981, I-65 in the south of Birmingham was completed and in 1984, I-459, the Birmingham bypass, opened. In 1985, the last section of I-65 opened in Alabama, exactly the portion that connected with the first open section of I-65.
The newest long Interstate Highway is Interstate 22, which was initially constructed as US 78 as a freeway and has been numbered I-22 since 2013. The last missing section of I-22 in Birmingham opened to traffic in 2016.
There are plans for the large-scale construction of new freeways for Alabama, but there is a lack of funding to actually implement this. For example, it has been suggested for years to extend I-85 west from Montgomery to I-20 near the Mississippi border. The northern ‘Beltline’ is being built around Birmingham, Interstate 422, of which construction of a small part started in 2014, but there is no prospect of financing for the entire bypass. Around Montgomery, I-85 shifts south on the Montgomery Outer Loop. Here too, only a small part has been completed without concrete financing for other parts.
Alabama is known for its colorful signage. Signposts are placed in deep dark green, almost against the black. Also, another type of reflective surface is used. Alabama does use the regular Manual on Uniform Traffic Control Devices (MUTCD) without additions.
Congestion is rare in the state. There can be some short traffic jams in the big cities, mainly due to incidents. There is certainly no question of large-scale congestion. The biggest bottleneck is I-20/59 past Birmingham city center and the interchange with I-65, also known as the ‘Malfunction Junction’.