Interstate 40 in Arizona Interstate 40 in Arizona Interstate 40 (I-40) is an east–west Interstate Highway that has a section in the U.S. state of Arizona, connecting sections in California and New Mexico. The section throughout Arizona is also known as the Purple Heart Trail. It enters Arizona from the west at a crossing of the Colorado River southwest of Kingman. It travels eastward across the northern portion of the state connecting the cities of Kingman, Ash Fork, Williams, Flagstaff, Winslow, and Holbrook. I-40 continues into New Mexico, heading to Albuquerque. The highway has major junctions with U.S. Route 93 (US 93) — the
Arizona State Route 143 Interstate 10 and US 60 between the Mini Stack and the Broadway Curve, adding to additional traffic overload and safety issues at the interchange with SR 143/I-10/US 60. The speed limit on I-10 throughout the city of Phoenix is currently . Many other area freeways have limits of , notable exceptions being the Sky Harbor Expressway with , Arizona 51 south of Glendale Rd with 55 mph, and Interstate 17 with . Arizona State Route 143 Arizona State Route 143, also known as SR 143 and the Hohokam Expressway, is a north–south and access-controlled freeway in Maricopa County, Arizona, that