unfeasible for I-465, so a 91st Street alignment was initially proposed. This proved to be controversial and caused many delays in final alignment selection for the north leg, postponing its construction by several years. Initial construction (1959–1970) The I-465 beltway was constructed in segments. There were 16 segments along the original proposed semicircumferential alignment between I-65 in Boone County at exit 129 and that same highway to the south at exit 123 in Marion County. Indiana highway officials recognized the value of having the route be a full circumferential, so using non-Interstate federal funding and employing a temporary designation of SR 100, they planned a separate 17th segment northward between I-65 at its exit 123 and the north leg of I-465 in Boone County. By the time that added section was completed in 1970, Indiana had obtained federal approval to sign it as I-465 as well, resulting in the creation of a dogleg section of I-465 outside of the loop (now signed as I-865). State highway officials concentrated on building the west and south legs of I-465 early in the overall project, since they were the missing portions of the SR 100 concept. Construction began in 1959, and the first section of the I-465 beltway to be completed was the portion on the west leg between I-65 near Eagle Creek Park and I-74/US 136 in Speedway. That section was opened to traffic on September 26, 1961, simultaneously with the adjacent section of I-65 northwest from there running to 71st Street. By July 18, 1962, all four segments of the original west leg were open between SR 67 (Kentucky Avenue) and I-65, but the interchange with I-70 in that stretch was not completed until much later that decade when the segment of that route from I-465 west to SR 43 opened in 1968. The south side sections were the next to be completed, with three opening in the second half of 1963 and two more on October 15, 1964. This completed both the south leg and the first segment of the east leg and included a connection from a point just north of the Raymond Street grade separation to SR 100 (Shadeland Avenue) at Washington Street (US 40). With these sections open, the full length of I-74's concurrency over I-465 was now available for motorists. The south leg's junction with I-65 was also completed, but I-65 itself was open only between