Texas-based Jacobs Engineering and Boston's McCourt Construction are constructing a $99.2 million project in Natick, Mass., replacing a bridge and introducing Massachusetts's first diverging diamond interchange. The redesign aims to enhance safety, mobility and reduce traffic congestion, with completion expected by mid-2030. The project includes new shared pathways, transit stops and traffic improvements to accommodate the daily flow of over 80,000 vehicles. The design-build method allows for efficient collaboration and streamlined construction process.
MassDOT render
A render of the proposed diamond interchange in Natick.
Jacobs Engineering, a design firm based in Dallas, Texas, along with its design-build partner McCourt Construction in Boston, Mass., is working replace a bridge and install a new interchange at a critical road junction in the city of Natick, Mass.
Located at the intersection of Massachusetts Highway 27/North Main Street and state Highway 9/Worcester Street, the $99.2 million Natick Bridge Replacement and Interchange Improvements Project also will introduce the state's first diverging diamond interchange (DDI) to enhance safety, mobility and reduce traffic congestion in the Boston suburb.
The new configuration in Natick will take the place of the existing partial clover leaf interchange.
Its design-build team was selected August 2024 by the Massachusetts Department of Transportation (MassDOT).
As lead designer, Jacobs will oversee the replacement of the Mass. 27/North Main Street bridge in Natick with two new single-span bridges and a dedicated shared-use-path bridge for pedestrians and cyclists. The redesigned interchange will use a modified DDI configuration to eliminate left turns and reduce vehicle-to-vehicle accidents by up to 50 percent.
Jacobs also will apply its StreetLight mobility analytics platform to support data-driven decision making. The platform will help minimize traffic disruptions during construction and guide the addition of shared-use paths that improve access to schools, transit and major employers throughout the region.
"The Natick Bridge replacement, a first-of-its-kind interchange in Massachusetts, exemplifies how infrastructure and data solutions together deliver lasting societal benefits," said Jacobs Executive Vice President Katus Watson in a company news release. "Using insights from our StreetLight platform, we'll keep traffic moving while delivering an innovative interchange design that improves safety and strengthens community connectivity."
The project also includes new accessible bike and pedestrian facilities and is expected to be completed by mid-2030.
According to MassDOT, crews will replace the existing North Main Street bridge over Worcester Street with three independent bridge structures — one for North Main's northbound vehicle traffic, another for the street's southbound drivers, and a third to accommodate the planned shared-use pathway.
Other aspects of the new interchange will include:
- four transit stops (two along Worcester Street and two along North Main Street) with corresponding bus shelters for the MetroWest Regional Transit Authority (MWRTA);
- a shared-use path along the south side of Worcester that will connect the North Main interchange area with the Cochituate Rail Trail (at the westerly project limit) and the MathWorks campus (at the easterly project limit);
- a new sidewalk along the north side of Worchester Street within the project's footprint;
- building a continuous shared-use path along one side of North Main and a sidewalk along the other side from Bacon Street to Rutledge Road;
- pedestrian-actuated warning systems at multiple crosswalk locations to increase driver awareness and yielding of crossing activity;
- two new traffic signals along North Main to accommodate the street's crossing traffic (associated with the function of the modified DDI);
- reconfiguring and improving access between Lakeshore Road and North Main Street;
- changing the traffic signal at North Main and the Mass. 9/27 Exchange Driveway;
- reconfiguring the Worcester Street on/off ramps to provide increased deceleration and acceleration lengths;
- upgrading and/or replacing existing drainage infrastructure along both North Main and Worcester streets within the project limits; and
- replacing the existing median barrier along Worcester.
Other ancillary items planned for the project are low maintenance landscaping, stormwater improvements, retaining walls, guardrails, pedestrian fencing, new signage and new pavement markings, according to MassDOT.
Old Natick Bridge No Longer Meets Safety Standards
In a description of the Natick Bridge replacement project on its website's project page, MassDOT said "the bridge that carries Route 27 over Route 9 is near the end of its useful life and needs to be replaced. In addition, the existing bridge … does not meet federal requirements for vertical clearance. The project design includes raising the profile of Route 27 so this requirement can be met."
The agency added that during its evaluation of alternatives for the bridge replacement, the challenge of construction staging was also identified. A key advantage of the modified DDI is that the new eastern bridge can be built "off-line" — eliminating the need for a temporary bridge during construction.
As far as the need for enhanced safety and a reduction in traffic congestion at the Natick interchange, MassDOT noted that the on ramps to Mass. 9/Worcester Street have been identified as the first and second highest crash locations in Natick, with more than 100 accidents occurring there each year.
"The project will address this by eliminating the weaving condition that occurs on Route 9 caused by the Route 27 on and off ramps," according to the state transportation department. "This will be achieved by reducing the number of ramps and adding deceleration and acceleration lanes on Route 9 so that traffic doesn't need to stop before entering [the road].
"On average, more than 80,000 vehicles travel through this interchange each day," MassDOT said. "During peak weekday travel times, Route 27 experiences significant delays, with vehicles frequently queueing on the Route 9 on-ramps. Studies have shown that DDIs can reduce delays from 15-60 percent. This project will provide a more efficient design to better manage this demand while safely accommodating all mobility needs of the community.
By using the design-build project delivery method, where a single team manages both the design and construction in a single phase, the need for a separate construction bid based on finalized plans and specifications is also eliminated. Design-build also streamlines the process by reducing project timelines and fostering collaboration among designers, contractors and the MassDOT team.
The delivery method also enabled McCourt-Jacobs to begin early construction on some project components while final design is still underway.
MassDOT said it is using design-build more frequently because the practice promotes innovation, reduces the owner's project risk and expedites project delivery.
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