Cape Cod traffic can be a headache, especially during summertime holidays, and it’s expected to only get worse.

By 2040, state officials expect the number of vehicles crossing the two bridges connecting the Cape to the rest of Massachusetts on an average summer to increase nearly 27 percent — from 122,000 currently to 154,900.

“Traffic operations are forecast to degrade, with substantially more freeway and interchange locations operating at less acceptable levels,” Massachusetts Department of Transportation officials wrote in a report released Wednesday,

However, they’re working on a plan to address the issue.

Following a five-year study, MassDOT’s report this week proposed several ways of improving traffic conditions around the Bourne and Sagamore bridges, the two sole options for traversing the Cape Cod Canal by car. The tall, narrow 84-year-old structures have become as notorious as they are iconic — if not more so — as the Cape’s population boomed over the second half of the 20th century. And according to state estimates, the region’s 213,413-person population nearly doubles during the summer tourism season.


The U.S. Army Corps of Engineers is expected to release a report this summer on their own multi-year study on replacing the two aging overpasses, but wider bridges alone won’t be enough to relieve the pressure. Here’s what MassDOT is proposing:

Scenic Highway to Route 25 Westbound Ramp

According to the study, a new entrance ramp from the Scenic Highway, which runs east-west on the north side of the canal, onto Route 25 north of the Bourne Bridge would divert 40 percent of westbound vehicles from Belmont Circle, a somewhat chaotic, oblong quasi-rotary that has been a source of traffic buildup.

Belmont Circle Reconstruction

Speaking of which, MassDOT is also suggesting reconfiguring Belmont Circle. Officials studied several alternatives to current construction and decided the best approach would be to replace the circle with a three-leg roundabout, along with a signalized intersection. During the summer, they said the reconstruction would reduce peak traffic lines from more than two miles to 870 feet.

Bourne Rotary Interchange

Officials also have big plans for the other side of the Bourne Bridge. According to the report, they suggest reconstructing the current Bourne Rotary into a highway interchange with three adjacent traffic-light intersections. The change would “substantially reduce peak period queuing” in the area, which currently experiences “unacceptable” delays during peak periods.


Relocation of Exit 1C

On the Cape side of the Sagamore Bridge, officials suggest relocating Route 6’s Exit 1C by nearly two-thirds of a mile east so that drivers aren’t merging onto the highway immediately before the bridge. The plan would create a new ramp to Route 6 from the intersection of Route 6A and Route 130, which would be turned into a four-way roundabout. Officials say it would reduce the peak summer Saturday delays for drivers leaving the Cape from 13.5 minutes to 3.5 minutes.

MassDot officials are also recommending an additional eastbound travel lane on Route 6 for roughly 3.4 miles until Exit 2.

With the proposed improvements, officials are also recommending redesigning both bridge approaches. And while the alternatives were developed to be compatible with either the existing or replacement bridges, the plan says it is “assumed” that the Army Corps will conclude both canal bridges need to be replaced. MassDOT envisions multi-modal crossings that are much wider than the two current tight two-lane spans.

Potentially a total of 138-feet wide (compared to the current 48-foot-wide bridges), the replacements would include two through lanes in each direction, auxiliary lanes for vehicles entering or exiting the highway, and a 10-foot median. Officals wrote that the concept would alleviate the traffic bottleneck common on both bridges.

The proposed bridges also include sidewalks on both sides and a single 12-foot shared-use path for cyclists and pedestrians. The report also suggested improving bike access around the bridges.

There’s still a number of steps in the “complex decision-making process” before any of the recommended changes would be implemented. MassDOT is accepting public comments on the report through June 20.


According to their estimates, if the state decides to go forward with all of their proposals, “Case 3A,” the improvements would cost a total of $542 million by 2040. However, officials say it would provide a host of economic and time-saving benefits for local residents, businesses, and — of course — travelers.