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).

The city council confirmed that the 10 primaries affected will remain closed for the rest of the week.
Contingency plans are being put in place for the five high schools with pupils being phased back to the classroom from Wednesday onwards.
All the schools in question were constructed under the same public private partnership contract.
They were built by Miller Construction, which was acquired by Galliford Try in 2014.
It has been confirmed that Gracemount and Craigmount high schools, plus Oxgangs and St Peter's primary schools, will need urgent repairs before opening their doors once more.
Every Scottish council has either carried out or is going to carry out surveys of school buildings that could be affected.
Edinburgh Council hoped that all primary and special needs pupils would be able to return by the start of next week.
However, the 7,000 youngsters affected on Monday will remain off school on Tuesday.
Officials said that "significant work" had been undertaken to ensure that 2,000 S4, S5 and S6 pupils would be accommodated as soon as possible.
Alternative arrangements will need to be worked out for all S1 to S3 pupils.
Edinburgh University, the Scottish Parliament, community groups, venues and private sector companies have all offered help.
The local authority confirmed that structural surveys would continue to be carried out this week.
The closure of the schools, which are about 10 years old, was prompted after workers repairing serious structural issues at one city primary found "further serious defects" with the building on Friday.
Edinburgh Schools Partnership (ESP), which operates the schools, could not provide safety assurances and that is why the 17 schools remained closed after the holidays.
Lindsay Cairns' daughter is in primary one at Oxgangs Primary School.
She said: "I don't know if I'm going to have to have time off next week to look after her.
"I've spoken to my manager. We have to wait and see what the council are going to come back with.
"I'd like to think there's going to be an update and a contingency plan put in place but to me I'd rather have had that contingency plan before now."
Rachel Bhandari's son is nine years old and has cerebral palsy. His special school is closed until further notice.
She and her husband have spent the weekend trying to organise childcare as they both work.
Ms Bhandari said: "It presents us with a really big difficulty really. We were expecting the school to be open.
"We were told earlier in the week that it was going to be open and then just to find out on Friday that it's not is a nightmare."
The problems were first uncovered in January when a wall at Oxgangs Primary collapsed during high winds.
Three other schools were later closed after inspections revealed problems with the way walls had been built.
Amy, 16, a pupil at Firrhill High School, told BBC Scotland: "It's quite disruptive because we need to finish the coursework and we need to do unit assessments, and they were meant to be happening this week but now they'll have to be done later.
"It's been open for 10 years, the part of the building that was built, and it hasn't fallen down yet. There's no storm just now. Nothing's going to happen."
Heavy snowfall has created a huge traffic jam on a major motorway in Russia, trapping thousands of vehicles.
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Urgent work will be required on several of the 17 Edinburgh schools which were closed due to safety fears.