The Arizona Department of Transportation advises drivers that US 180 will be narrowed to one lane of alternating north- and southbound travel on Friday because of pavement-preservation work.

The work is scheduled from 7 a.m. to 5 p.m. Motorists should plan for delays of 20 minutes or more while work is underway. Traffic-control personnel will direct motorists through the work zone.

Crews are working in 4-mile increments along a nearly 18-mile work zone just outside of Valle, east of Flagstaff.

The restriction is needed while crews apply a pavement surface treatment, which helps extend the life of the roadway.