Media reports put the length of the traffic jam in the north-western Tver region at up to 200km (124 miles) - but officials said it was about 20km.
The officials said field kitchens had been operating on the M-10 motorway, although some drivers complained that supplies never reached them.
After three days of chaos, traffic was reportedly returning to normal.
The motorway began clogging up in the early hours of Friday because of heavy snow and ice.
"Drivers help one another and that's it: the problems are on the side of the authorities," lorry driver Sergei told Rossiya 24 TV.
"There are no petrol tankers, no water, nothing, we are just stuck here," he added.
Another driver was quoted in the local media as saying that he only managed to move forward one kilometre on Sunday and was feeling cold in freezing temperatures.
The Russian authorities said late on Sunday that they had managed to unblock the traffic jam and vehicles on M-10 were now moving at 90km/h (55mph).
Heavy snowfall has created a huge traffic jam on a major motorway in Russia, trapping thousands of vehicles.