US 431 - Guntersville to Huntsville, Alabama

U.S. Route 431 (US-431), internally designated by the Alabama Department of Transportation (ALDOT) as State Route 1 (SR-1), is a major north-south state highway across the eastern part of the U.S. state of Alabama. Although US-431's south end is in Dothan, SR-1 continues south for about 13 miles (21 km) along US-231 to the Florida state line.
One of the criticisms of US-431 in its entirety from Kentucky to Alabama was that it was mainly a two-lane road. ALDOT has prioritized four-laning the route in Alabama as a viable north-south road corridor in the eastern part of the state.
Of particular concern was the segment from Seale south to the Barbour County line, where rolling hills along the original alignment limit the visibility of oncoming traffic, contributing to poor decisions by motorists to pass, resulting in numerous head-on collisions. In this segment alone, 31 people were killed in crashes between 1992 and 2006, leading Readers Digest to proclaim it one of "America's Deadliest Highways" in 2000. After being contacted by and subsequently meeting the family of a fatal crash victim in 2003, ALDOT Director Joe McInnes decided to expedite the construction on the last remaining stretch of two-lane road between Seale and the Barbour County line. This 16-mile (26 km) section was completed and opened in late 2010. The old alignment in Russell County is still open to traffic and is now labeled County Route 137.
Traveling south from Tennessee, as of mid-2009, US-431 is a four-lane route to Oxford. Then, after diverting from I-20 east of Oxford at exit 191, it reverts to a two-lane highway southward to Opelika, with a brief four-lane stretch just south of Wedowee. From Opelika southward to its southern terminus in Dothan, US 431 is now open as a four-lane highway.