Work on the I-89 exit 16 in Colchester has begun. Here's a look at the timeline and end goal.

Lilly St. Angelo, Burlington Free Press
·2 min read

Construction workers have begun work on the I-89 exit 16 in Colchester.

The $14 million project, in the works since 2012, began this winter and will completely redesign the busy exit, creating a diverging-diamond interchange that will weave cars more safely and effectively to their desired destinations, according to the Vermont Agency of Transportation's project website. The work will span from now until the summer of 2026.

Before work begins on the new roadway design, preparations must be completed.

A rendering shows what the diverging-diamond interchange would look like from a car's perspective. The full project is estimated to be complete by summer 2026.
A rendering shows what the diverging-diamond interchange would look like from a car's perspective. The full project is estimated to be complete by summer 2026.

What to expect this year

S.D. Ireland is executing the first phase of the project right now, and they've estimated to finish the work by the end of the fall. The work includes relocating utilities, replacing waterlines, removing ledges as well as retaining wall and drainage work. Members of the public can sign up for email updates on the project website to stay in the know about road closures and blasting schedules.

The next phase of construction, which will be under a separate contract, will begin in Fall 2024. This is when the diverging-diamond interchange will be created.

A view of winter construction progress on the retaining wall under the I-89 bridge at exit 16 in Colchester. The retaining wall creates space for a shared-use path that will run parallel to the road.
A view of winter construction progress on the retaining wall under the I-89 bridge at exit 16 in Colchester. The retaining wall creates space for a shared-use path that will run parallel to the road.

What is a diverging-diamond interchange?

A diverging-diamond interchange is a modern traffic design that eliminates the need for left turn lanes onto highway ramps and the traffic congestion and safety concerns they create.

In a diverging-diamond interchange, drivers go through a light before going under the I-89 bridge, much like they do now, except the option to enter the on-ramp to the highway to their right happens before they get to the light. Instead of going straight at the light, however, all drivers curve to their left and are on the left-hand side of the road as they drive under the bridge, giving them the opportunity to take an on-ramp to the highway without a left turn. If drivers continue through without getting on the interstate, they encounter another light just after going under the bridge and curve back to the right as they go through the intersection.

A bird's-eye view rendering shows the diverging-diamond design that will be constructed at I-89 exit 16 in Colchester. The first phase of construction is underway but the bulk of the road work will begin in 2024.
A bird's-eye view rendering shows the diverging-diamond design that will be constructed at I-89 exit 16 in Colchester. The first phase of construction is underway but the bulk of the road work will begin in 2024.

The dance-like pattern can be seen from a driver's perspective and from above in animation videos on the project website. According to the VTrans, the design will create a less stressful, more time-efficient experience for drivers.

The medians created from this design help pedestrians more safely cross intersections like these and also significantly reduce wrong-way interstate entrances.

Contact Urban Change Reporter Lilly St. Angelo at lstangelo@gannett.com. Follow her on Twitter: @lilly_st_ang.

This article originally appeared on Burlington Free Press: Vermont road work: What is happening at the Colchester I-89 exit 16