Construction of Loop 303 will begin early in 2009 when the Arizona Department of Transportation (ADOT) temporarily re-routes Happy Valley Parkway to make way for a new freeway overpass. The new bridge will carry Loop 303 up and over its intersection with Happy Valley Parkway.

During its construction, traffic on Happy Valley will move to a new temporary alignment that gives construction crews plenty of room and keeps the motoring public safe.

ADOT estimates that construction of the overpass will take about one year. During that time, the intersection of Loop 303 and the Happy Valley realignment will be controlled with a three-way stop. Speed will be limited to 25 miles-per-hour in the construction zone.

North of the Happy Valley intersection, Loop 303 will turn east on approximately the Lone Mountain Road alignment and be extended to I-17 in phases. This first phase includes a four-lane divided roadway from Happy Valley Parkway to I-17 and interchanges (overpasses and underpasses) at Happy Valley, Lone Mountain and Lake Pleasant parkways, as well as an interchange with I-17 at Lone Mountain Road. Phase one is expected to be complete in 2012.