An ambitious project to rehab Interstate Five in Siskiyou County launches Monday. Cal-Trans is planning a total of 500 work days for completion of the project, which will rehabilitate the freeway pavement and replace some bridge decks from the Central Dunsmuir Undercrossing to the Black Butte Overhead. There will be lane closures, traffic reconfigurations and a 55 mile per hour speed limit throughout the multi-year project.