Snow falling throughout the day has left wet spots on the roads that are icing over and causing dozens of crashes and spinouts as temperatures drop.
State police said slick roads are causing problems "all over the place."
"Troops are very busy tonight with crashes due to this awful weather," said state police spokesman Sgt. Shane Hassett.
Most crashes have been minor, but a collision on Interstate 84 westbound in Farmington shut down the highway near exit 39 for a period of time Saturday evening. Emergency responders searched an embankment off the side of the highway and found a car rolled over in the woods.
Hassett said the driver was hospitalized for treatment of minor injuries and received a verbal warning for traveling too fast.
Emergency crews are also responding to a crash and major fuel spill on I-84 westbound just prior to exit 69 in Tolland, where a tractor-trailer collided with several cars and leaked 150 gallons of diesel fuel onto the highway. Officials said traffic has been affected on both the eastbound and westbound sides of the highway.
Route 8 southbound was also closed in Derby near the Shelton town line while emergency crews respond to a six-car pileup, according to firefighters. Officials are also responding to a crash on Route 8 northbound between exits 11 and 12.
State police said they've responded to two dozen crashes on I-84 in the Danbury area alone. A number of additional incidents have been reported on I-84, Route 8, I-91 and I-691. Police said Route 15 is also a sheet of ice.
Snow will continue falling past midnight and temperatures will dip down into the 20s overnight. Skies will clear Sunday, with highs near 40.