New bridge links are needed for Cape Cod, in the US state of Massachusetts. Two bridges spanning the Cape Cod Canal will need to be replaced, according to the US Army Corps of Engineers. The existing Bourne and Sagamore bridges spanning the Cape Cod Canal both date from the mid-1930s and are unable to cope with current traffic volumes. When the two bridges were built, just 26,000 people lived on Cape Cod. However the local population is now close to 220,000 and set to grow further.
The 727m long Bourne Bridge opened to traffic in summer 1935 and carries Route 28, with a 41m clearance over the canal. Meanwhile the 429m Sagamore bridge carries Route 6. Both bridges feature heavy congestion at peak periods. Official estimates suggest that traffic levels will increase 27% during the summer and 32% during the rest of the year, with the Sagamore Bridge carrying the majority of the vehicles.
The two structures are ageing and now have to be maintained regularly, with closures and traffic restrictions being common, further increasing journey times and queues for drivers. Unless they are replaced, the two bridges will need a further programme of major repairs and maintenance in six years-time.
According to the US Army Corps of engineers, which originally built the structures, these bridges are functionally obsolete. However it is worth noting that their structural condition is fair and not a matter for immediate concern. Replacing the two bridges and building new road links to improve traffic flow is expected to cost US$1 billion.
The Cape Cod Chamber of Commerce and the Cape Cod Regional Transit Authority are both strongly in favour of replacing the existing bridges. The current traffic delays provide a serious brake on economic activity in the area.
The US Army Corps of Engineers is proposing having the new bridges and road links open to traffic by 2025, as this would avoid having to carry out the major maintenance work that would otherwise have to be carried out on the existing structures.
The existing bridges have lanes that are too narrow to meet modern standards and also have inadequate provision for pedestrians and cyclists. Building two new bridges would improve capacity and safety for drivers.
Other options would include repairing the structures. However, given their inability to cope with traffic volumes, the fact that they do not meet modern requirements on lane widths and that they will require further periodic maintenance makes this less suitable.