Vermont’s First Diverging Diamond Interchange

The Vermont Agency of Transportation (VTrans) is improving the roadway along the U.S. Routes 2/7 (U.S. 2/7) corridor, in the vicinity of Interstate 89 (I-89) Exit 16, to enhance mobility and safety in Colchester, Vermont. The project area extends from in the Colchester-Winooski town line north for approximately 1 mile to just beyond the intersection of Sunderland Woods Road at U.S. 2/7. The core of the project is to reconfigure the existing tight diamond interchange to a Diverging Diamond Interchange at I-89 Exit 16.

Learn more about this and other improvements

Image of Interchange

Project Updates

Exit 16 DDI Construction Public Meeting

The Vermont Agency of Transportation (VTrans) invites you to attend a Construction Public Meeting for the Exit 16 Diverging Diamond Interchange (DDI) Project

Monday, October 10, 2022 6:30 PM

Join in person: Colchester Meeting House located at 830 Main Street, Colchester, VT.

Join remotely via Zoom Webinar:

To dial in by phone, please call +1 646-558-8656

Type in the Webinar ID: 851 1737 2822

When joining by phone, please press *9 to raise your hand to be called on and *6 when asked to unmute.


Read more

VTrans Awards Construction Contract for the Exit 16 DDI Project

On Monday, August 22, 2022, the Vermont Agency of Transportation awarded the construction contract for Phase 1 of the Exit 16 Diverging Diamond Interchange (DDI) Project to S.D. Ireland Brothers Corporation. The construction contract was awarded at an estimated cost of approximately $7.5 million.

Work in Phase 1 will include utility relocation, waterline replacements, telecommunications duct bank installation, ledge removal, and the construction of retaining walls. Updates to the anticipated construction schedule will be developed over the upcoming weeks. Please continue to check the website for updates or sign up to receive project related announcements directly to your email!

Updated Project Schedule Announced

VTrans has announced an updated schedule for the Exit 16 Diverging Diamond Interchange (DDI) project.

Construction of the Exit 16 DDI project will be completed in two phases under two separate construction contracts which will be executed sequentially. The bid advertisement and the contract award for the first contract, Phase 1, are planned for Winter/Spring 2022. Once awarded, phase one of construction will begin, which includes utility relocation, waterline replacements, telecom duct bank installation, ledge removal, and the construction of retaining walls. Phase 1 is anticipated to be completed by Spring 2023. Phase 2 is anticipated to be bid advertised and awarded in Summer 2023 and completed by Summer 2025. Phase 2 will consist of the bulk of the roadway work including the installation of the DDI, the addition of turning lanes, and the implementation of pedestrian and bicycle accommodations.

Visit the Project Overview page for more information. 

Act 250 Ruling

On November 6, 2020, the Vermont Supreme Court affirmed in favor for the State of Vermont a decision to issue an Act 250 permit for the Vermont Agency of Transportation’s (VTrans) Exit 16 DDI project after challenges to its previous issuance by the Natural Resources Board’s District #4 Environmental Commission. This decision and affirmation is welcomed by VTrans, the Vermont Agency of Natural Resource and the Natural Resources Board, and reinforces VTrans’ desire and ability to improve transportation conditions for all users along this regionally important corridor while being environmentally sensitive to the project area, Sunnyside Brook and Lake Champlain.

Driving Animations

Experience Exit 16 DDI

Driving simulation traveling on US 2 West / 7 North through the DDI

Aerial view of the operating diverging diamond interchange at I-89 Exit 16

Driving simulation exiting I-89 onto US 2 East/7 South via Exit 16

Driving simulation traveling on US 2 East/7 South through the DDI

Driving simulation exiting I-89 onto US 2 West / 7 North via Exit 16