The bridge, which is located on Route 66 near city hall, was built in 1934 as a part of the original Route 66 construction. Planned excavation efforts will clear more of the Rio de Flag wash than needed to set the stage for the city’s future flood control projects.

Crews recently completed a retaining wall on the north side of the bridge and are now working on a retaining wall on the south side.

Construction work is scheduled weekdays from 6 a.m. to 5 p.m. through Monday, Feb. 8. Towards the end of February or in early March, crews will begin the six-week process of drilling shafts for the foundation of the new bridge

Drivers can expect eastbound travel lanes to be shifted to the north by one lane and the left-turn lane to northbound US 180 to be closed during construction. The speed limit between Butler Avenue and Beaver Street will be reduced to 25 mph.

A traffic shift was implemented earlier this week that will remain in place until Jan. 22, Harding said. 

Two lanes of traffic in each direction will continue to operate while left-turns at Humphrey’s Street are restricted. Traffic along Route 66 will be detoured to north San Francisco Street to west Columbus Avenue to access northbound US 180.

"Drivers should proceed through the work zone with caution, slow down and watch for construction personnel and equipment,” according to a release from ADOT.

A seven-day full closure of  the area along Route 66 is planned in the spring, during which the existing bridge will be removed with the new bridge taking its place.

The $4.9 million bridge replacement project is a joint effort involving the City of Flagstaff, Arizona Department of Transportation and Federal Highway Administration.