A long queue of vehicles forms just before the Exit 17 on ramp last week. Planners are looking at ways to ease congestion at the vital intersection. (Photo by Courtney Lamdin)

A long queue of vehicles forms just before the Exit 17 on ramp last week. Planners are looking at ways to ease congestion at the vital intersection. (Photo by Courtney Lamdin)

The deteriorating bridge and dangerous traffic patterns at Colchester’s Chimney Corners Interstate 89 interchange has prompted regional planners to expedite a reconstruction project there, officials said last month.

The intersection, where Routes 2 and 7 meet at Exit 17, is choke point for Milton and Champlain Islands commuters and proves a daunting labyrinth for cyclists.

There are two state-ranked high crash locations on the north- and south-bound ramps. Data shows 48 crashes, 18 with injuries, between 2008 and 2012

All this has prompted the Chittenden County Regional Planning Commission to focus on long-term fixes.

“It’s beyond the point of rehabilitation, CCRPC Project Manager Jason Charest said, addressing the Colchester Selectboard last Tuesday.

Charest presented the Colchester and Milton selectboards with two redesign options, seeking feedback to forward to the Vermont Agency of Transportation.

One option involves widening the bridge from the current three lanes to six. The second, less-costly option involves a more modest bridge-widening — keeping three lanes but adding bike shoulders — and adding a looping on-ramp for southbound interstate traffic intersecting with Route 2.

Both options involve reworking the myriad merges, on-off ramps and T-shaped intersections. Colchester Rep. Pat Brennan, chairman of the House Transportation Committee, estimated the project could take 10 years to finish.

The Colchester Selectboard unanimously endorsed the looping on-ramp, following a recommendation from Colchester Public Works Director Bryan Osborne.

Traffic engineer Joe Barr cautioned this option will require government acquisition of private property and wetland mitigation, both which add uncertainty to the project cost and timeframe.

“There are wetlands, and we feel like we can move and reconstruct them with minimal impact on the environment,” Barr said.

CCRPC estimates the cost at $17 million, compared to the $22.6 six-lane bridge option. Both include demolition, construction and 30 percent contingency and would be 90 percent covered by Federal Highway Administration dollars and 10 percent with VTRANS funds.

Ten years is a long time to wait to fix a situation where rush hour traffic occasionally backs up before off-ramps and where even experienced cyclists avoid the series of intersections. CCRPC projects up to a 35 percent increase in traffic volumes in the next 20 years.

Charest said short-term improvements such as adding smart traffic lights to detect long backups and extended green time will be considered in the interim.

“The safety issues are such that some sort of short-term mitigation will have to be put in place before the bridge is ready to be replaced,” said Michele Boomhower, CCRPC assistant executive director.

Cyclist Amy Otten, speaking at the Colchester meeting, commended planners for including wider shoulders on the bridge that flow into dedicated bike lanes in the long-term plans.

“Thank you very much, from all the cyclists, for all the improvements,” she said, “because right now it’s awful through there.”

Milton’s Selectboard members wondered, though, whether Exit 17A – the long-talked-about, dedicated Milton exit, featured in the town’s comprehensive plan – was considered as an alternative to this project, or in addition.

Selectman John Gifford said another exit would ameliorate traffic congestion for Milton commuters. Business owner Bill Daley agreed, saying CCRPC is missing an opportunity if it doesn’t consider un-shelving the project, which he thinks would stimulate the local economy, not to mention help his business, Gray Rock Quarry, sited off West Milton Road where the exit was once imagined.

Boomhower said VTRANS wants to address connectivity but prefers to maintain existing infrastructure to building new, and the bridge needs replacing before and if Exit 17A is ever built. Charest said the area is part of a separate Route 7 corridor traffic analysis.

The planners said the new design won’t perfect the intersection and traffic flow, just improve it. With the loop design endorsed, CCRCP expects to complete a scoping report by July. From there, CCRCP will discuss with VTRANS when the project could be funded and built, Charest said.