First conceived in the 1970s, the new 3.8-mile limited access bypass has improved safety, capacity and reliability while also setting the stage for transformation of Hillsborough’s business district. Finished under two contracts, the project included two single-span crossings of an active railroad—a 230-ft-long bridge with a 61-degree skew and a 176-ft-long bridge with a 16-degree skew.

Early design-phase consultation with steel fabricators prevented disruption during construction. Bridges span the railroad right-of-way, allowing for future tracks to accommodate expanded freight and passenger service. Because the bypass alignment crosses environmentally valuable land, large farmland tracts were preserved to meet community initiatives. In addition to developing a reforestation plan to offset removal of 47 acres of trees, soil sampling of properties in the construction corridor assessed potential residual contamination.

The project’s utility relocations included a major underground fiber-optic trunk line, a 30-in. water distribution main, four transcontinental gas pipelines and a sanitary sewer pipe system as well as advance installation of new 69-kV electric transmission lines.

Routing traffic around Hillsborough has significantly eased central business district congestion. The bypass also provides convenient access to a planned passenger rail station within walking distance of a proposed town center. The $42.2-million project was completed at budget and ahead of schedule in 41 months.