Traffic jams on the UK's major roads could reach a peak next month, new figures show.
Analysis of queues during the 12 months to August found that November 2016 was the worst with almost 170,000 hold-ups - some 50% above average.
The analysis by transport data company Inrix found that drivers faced 1.35 million traffic jams in the past year, costing them an estimated £9 billion in wasted time, fuel and unnecessary carbon emissions.
Inrix chief economist Dr Graham Cookson said: "There are so many factors that influence congestion levels it's hard to be certain why November was the worst month.
"We do know November 2016 was significantly colder than usual, in fact, the coldest month of the calendar year.
"The risk of ice on the road can lead to slower moving traffic and people are more inclined to take shelter in vehicles over cycling or walking in cold snaps."
The worst queue of the year occurred on August 4 on the M5 northbound near Junction 20 near Clevedon, Somerset.
Traffic tailed back 36 miles at the peak of the 15-hour jam, caused when an accident involving two lorries created a fuel spill and led to the closure of two lanes.
Mr Cookson said: "Fuel spillages, emergency repairs and broken-down lorries contributed to the biggest pile-ups this year.
"We advise motorists use the latest real-time traffic technology to keep up to date with the situation on the roads."