A jackknifted tractor-trailer has closed westbound I-84 between Exits 4 and 3 in Danbury. Traffic is being detoured off the highway because of the accident that was reported at 4:06 a.m. according to the state Department of Transportation. The accident is causing a significant westbound traffic backup. There’s no word yet on when the road will reopen or whether there are any injuries from the crash. While no cause of the crash has been determined, I-84 has a light accumulation of snow on the highway.