New Warning System Aims to Prevent Trucks from Striking Dexter Viaduct

Photo: The planned over-height flashing light system will be placed before the Main St bridge near the fire station. Photo by Doug Marrin

One of the major points addressed during the Washtenaw County Road Commission’s (WCRC) recent public meeting on the planned Dexter roundabout was the fate of the narrow 1893 railroad viaduct on Main Street.

The narrow stone arch is well known in Dexter as a trap for unsuspecting truck drivers, who sometimes wedge their rigs beneath it despite multiple warning signs along the approach. While the bridge itself will not be altered, county road officials announced the installation of a new over-height detection system designed to prevent large trucks from striking the structure.

How the System Works

Project Manager Kevin Dubnicki explained the system will use sensors to detect oversized vehicles before they reach the viaduct.

“WCRC understands numerous reported accidents occur every year at the existing viaduct, along with any unreported incidents,” he explained. “WCRC will include the installation of new over-height detection systems on Island Lake Road to the east within the city limits, West on the opposite side of the viaduct, and southwest on Dexter Chelsea Road. … The system works similar to a garage door beam to trigger the lights. … If it trips this or the over-high side, there will be lights that will go off before they reach the viaduct, allowing them to turn at either the roundabout or the opposite side on the west side of the viaduct to avoid an unfortunate incident there.”

Placement of Signs and Sensors

When asked where the system would be installed, Dubnicki said:

“The larger over-height truck turn right when flashing sign… will be in advance of the bridge as you were exiting Dexter. … The actual over-height detection pedestal, the 10 9” pole that you see on the right-hand side of the image, will be closer to where the fire station is. That’s where the warning system will be, where the actual trigger will be. It will be going across the roadway, so that they have enough time before they get to the roundabout and can navigate into the correct lane.”

He added that three approaches will be covered: 1) West of the viaduct, 2) Dexter-Chelsea Road, and 3) Main Street by the fire station.