at Madison's intersection with East Street, which formerly carried U.S. 31 from downtown to the south. The southern terminus was where Madison merges with existing U.S. 31 alignment in Johnson County just south of Smith Valley Road, south of Greenwood Middle School. The northern section of SR 431 was moved when the Keystone Avenue construction, along with the I-465 construction, was completed in 1967. Around 1965, SR 431 began at the junction of SR 37 at Fall Creek Parkway, north along Keystone Avenue to the interchange at 86th Street, then west along 86th Street (at the time, SR 100) to Westfield Boulevard, then north into Carmel. With the completion of I-465 in the area, SR 431 was removed completely from Westfield Boulevard. SR 431 was officially decommissioned on October 19, 2007, with the portions north of 96th Street being turned over to the city of Carmel. Carmel Mayor James Brainard immediately proposed banning heavy trucks from the route, the Hamilton County portion of which lies within his city's corporate limits. At this point, the street name was changed from Keystone Avenue (a designation that remains south of the county line at 96th Street in Indianapolis) to Keystone Parkway. Brainard also pushed for a plan to build six roundabout-style ("dogbone") interchanges on Keystone, built 2009–2010, in lieu of widening it to at least six travel lanes throughout. On December 30, 2019, another such interchange was opened at the junction with 96th Street. Major intersections References External links 431 Transportation in Indianapolis Carmel, Indiana Transportation in Johnson County, Indiana Transportation in Marion County, Indiana Transportation in Hamilton County, Indiana U.S. Route 31