The Fourth Street Bridge will be closed this weekend over Interstate-40 in Flagstaff. ADOT says the closure will run from 8 p.m. Friday until 5 a.m. Monday as work continues on the bridge replacement project. Pedestrians, bicyclists and emergency vehicles will have access across Fourth Street during the closure. Drivers can use Huntington Drive or Soliere Avenue as an alternate route. ADOT advises drivers to slow down and use caution around construction personnel and equipment while construction is underway.