Navigating Sixth Street is about to get more difficult for motorists.

Crews were to begin repaving portions of Sixth Street at 3 a.m. Tuesday, and city officials are warning that traffic delays are expected.

“There will be one lane of traffic open in each direction, but with the contractor’s equipment in there and all the workers, it is going to confusing,” said Chuck Soules, the city’s director of public works. “People are really just going to need to slow down and pay attention.”

The first phase of the project will mill and overlay Sixth Street between Kentucky and Massachusetts streets. The work will cause various lane closures on Sixth Street. The first phase of the project is expected to last for two days, weather permitting.

Crews then will move westward to repave Sixth Street from Kentucky to Missouri. Following that phase crews will repave Sixth Street until it reaches Iowa. The entire project is expected to last until Aug. 12.

Soules said the impact on morning traffic likely will be greater than on afternoon rush hour traffic.

“We have asked them to show up earlier rather than later, but they also will be playing it by ear with the weather,” Soules said.

The project comes as crews are finishing up replacing pavement on Sixth Street in front of City Hall, just east of Massachusetts Street. That project is expected to be completed by Wednesday, Soules said.

The Sixth Street repaving is in addition to construction already underway on Sixth Street between Folks Road and Monterey Way to add a center turn lane. That project also is expected to last until Aug. 12, Soules said.

Soules said city officials would have liked to have begun the Sixth Street repaving earlier in the summer, but a portion of the $1.2 million project is being paid for by the state. That required the project to wait until after July 1, the start of the state’s new fiscal year, to begin work.