The current Blue Belt runs relatively close to skirting the border of the City of Pittsburgh on all sides, though it does make excursions into border towns such as Dormont and McKees Rocks. It generally serves urban communities in the northern, southern, and eastern sectors of the county. In its path around the city, the belt crosses or joins PA 8, PA 28, PA 51, PA 88, PA 121, and PA 837. It also briefly joins US 19. Only a small portion of the route (on PA 28) is a freeway. The Blue Belt crosses the Ohio River via McKees Rocks Bridge between McKees Rocks and the Brighton Heights neighborhood of Pittsburgh, Allegheny River via Highland Park Bridge between Sharpsburg and the Highland Park neighborhood of Pittsburgh, and Monongahela River via Homestead Grays Bridge between the Pittsburgh neighborhood of Squirrel Hill and Homestead. As of 2016, sections of the Blue Belt have been closed, marked one way, resigned and/or rerouted. Construction and traffic flow are the believed primary causes.