Chelmsford Patch has received reports of an overturned tractor trailer truck on the onramp to 495 South from Route 3 South, just past the exit for Chelmsford Street.

Approximately half a dozen state and local emergency vehicles are on the scene, with other vehicles attempting to address the situation.

Traffic on 495 South is backed up at least to the Lowell Connector, although delays were difficult to ascertain at the scene due to snow creating poor visibility.

We will have more on this story as it becomes available.

For more up-to-date local traffic, check out our local commute page.