Snow caused slick driving conditions statewide leading to several crashes, including a series of crashes involving 25 to 30 vehicles on I-91 in North Haven.
Police and fire crews responded to the northbound side of I-91 around 11:45 a.m. to handle the multiple crashes between Exit 9 and Exit 11, according to North Haven fire officials.
The highway was shut down for several hours for what fire officials called a mass casualty incident.
Several ambulances were dispatched to the scene as well as a team of doctors from Yale-New Haven Hospital to treat any people who were injured.
The entire scene spanned about two miles, according to fire officials.
The highway reopened around 2 p.m.
State police said that between 10 a.m. and 8:30 p.m. they responded to 315 accidents and assisted 116 drivers.
A jackknifed tractor-trailer closed I-84 East in Southington late Tuesday afternoon.
Earlier, a crash closed Interstate 95 South in Madison, in the area of exits 61 and 60.
Interstate 95 was also closed in Old Lyme and in Stonington, but both have reopened.
Another crash closed Interstate 91 South in Rocky Hill.
There were also issues on Route 15 South in Hamden.
In East Windsor, police responded to a crash involving a school bus on North Road. No students were on the bus and police said it is a minor crash and the scene is in the process of clearing.
Check the new state Department of Transportation Web site, CT Travel Smart, for updates on traffic conditions.