In downtown West Sacramento, Business 80 and US 50 split from the West Sacramento Freeway, which is now locally maintained in part over the Tower Bridge up to the door of the capitol, but was once designated as SR 275. Business 80 crosses the Sacramento River on the Pioneer Memorial Bridge, intersecting with I-5 on the eastern river bank and the west end of unsigned Interstate 305. SR 99 once ran along I-5 to the north and Business 80 to the east, but this is now signed TO SR 99. Business 80 continues along I-305 to its eastern terminus, then turns north to follow SR 51 to its northern terminus at I-80.