PHOENIX (AP) — Construction of a new 22-mile (35-kilometer) freeway around much of the southern perimeter of metro Phoenix has reached another milestone.

The Arizona Department of Transportation says workers recently installed the last of over 1,000 girders needed for construction of 40 bridges for the Loop 202 South Mountain Freeway.

The 91-foot (28-meter) girder was installed at an interchange being constructed at Desert Schools Parkway in Ahwatukee (ah-wha-TU'-kee) in southeast Phoenix.

The South Mountain Freeway will run below South Mountain in south Phoenix to connect Interstate 10 at the Loop 202 Santa Freeway in Chandler and I-10 at 59th Avenue in southwest Phoenix.

ADOT says the freeway is expected to open to traffic by the end of 2019, providing an alternative to I-10 through downtown Phoenix.