Jacobs, in collaboration with McCourt Construction, has broken ground in Massachusetts on a monumental road infrastructure project: the state’s first Diverging Diamond Interchange (DDI). 

The project, which will take place at the intersection of Interstate 495 and Route 9 in Westborough, is expected to significantly improve traffic flow and safety in one of the region’s most congested corridors.

The business has been chosen to head the project’s design, with McCourt Construction overseeing the construction phase. The Massachusetts Department of Transportation (MassDOT) awarded the contract to the joint venture using a design-build delivery methodology, which streamlined collaboration and accelerated delivery. 

The department has awarded the Jacobs-McCourt team a $99.2 million design-build contract. The preliminary infrastructure work has already begun and main construction activities are anticipated to continue until mid-2030.

DDIs, unlike regular intersections, allow two directions of traffic to momentarily cross the other side of the street. This removes certain left-turn conflicts and has been proven to reduce crashes while increasing traffic throughput. The design is gaining popularity throughout the U.S. and this project marks its debut in Massachusetts.

“The implementation of the state’s first diverging diamond interchange demonstrates our commitment to providing innovative, proven solutions to address transportation challenges,” says Jacobs Senior Vice President Katus Watson. “This design improves safety and optimizes traffic operations while reducing environmental impact.”

The upgrade is projected to cost around $70 million and will include both reconfigured roads and additional pedestrian and cycling walkways. It upgraded signal systems and improved stormwater management. The final design will accommodate all means of mobility and comply with the Americans with Disabilities Act (ADA).

The I-495/Route 9 intersection is an important link in Massachusetts’ highway system, connecting commuters and freight traffic between Boston, Worcester and the surrounding towns. The project’s primary goals were to improve emergency response access, lessen delays caused by traffic and increase the region’s economic viability through better transportation infrastructure.

By 2027, Jacobs and McCourt are planning to complete crucial building activities. Because of a well-planned building strategy and continuous public education efforts, it is anticipated that traffic impacts will be minimal during this time.

The DDI project joins a growing list of innovative infrastructure improvements in the U.S. Similar design-build projects are ongoing in Texas and Florida, indicating a nationwide movement toward data-driven, safety-first road solutions.

As Massachusetts starts on this landmark project, it lays the groundwork for widespread adoption of next-generation roadway designs that promote safety, efficiency and multimodal mobility.