Sunday marks Day One of road construction in the area around St. Luke's, as the hospital prepares for a major expansion project on its downtown Boise campus.

The work is being done by St. Luke's Health System in conjunction with the Ada County Highway District and the city of Boise.

Detour signs and temporary traffic signals now surround the hospital to make way for several road improvements, including a two-lane roundabout at the intersection of East Fort and Reserve Streets, a cycle track around the hospital, and a dedicated right-turn from northbound Avenue B onto East Jefferson.

With all of these changes come road closures. Officials say as of Sunday night, Reserve Street is closed and will remain closed through October. Temporary traffic signals are installed at the intersection of First, State, and Fort streets as well as on Avenue B and East Jefferson Street.

Traffic will be reduced to one lane in each direction on Avenue B and Fort Streets beginning at Bannock and continuing through Second Street.

"During any construction it's challenging," said David McFadyen with St. Luke's. "It's short term pain, if you want to put it that way, or inconvenience for the longer term gain and the benefit to move around the campus better and with more flexibility in the future."

MORE: Fort Boise-St. Luke's area road work starts Monday: 'Just please be patient'

Crews are also starting to tear up asphalt and re-stripe traffic lanes on Sunday night.

McFadyen says this area was already pretty hard on commuters, so over the next several months, you should expect and plan for delays.