The morning rush hour has returned to pre-pandemic levels, the RAC said.
Analysis of cars with a black box fitted, carried out by the breakdown company between September 7 and September 16, suggested that since schools reopened the number of cars on the road in the morning has shot up.
The RAC said that there had been a “marked rise” in the number of cars on the road between 8am and 9am with volumes up by 55 per cent compared to the last week in August.
It said this suggested that it was the school run, rather than commuting, driving the return to the roads.
Rod Dennis, from the firm, said: “While schools reopening was always going to lead to a rise in vehicle traffic, the fact that between a fifth and a third of the UK workforce is still working remotely shows just what role the school drop-off plays in creating the phenomenon we know as the morning rush hour.
“In short, it appears dropping off children at schools and nurseries contributes far more to morning traffic in the 8am to 9am window than commuters heading to workplaces does.”
He said it was “abundantly apparent” how dependent parents are on the car for getting children to school, and that the reliance had only increased with people remaining nervous about getting public transport.
He added: “The staggered ‘drop-off windows’ introduced by many schools as a result of the pandemic to cope with large movements of children may be another reason for the rise.
“Those that have children in more than one school or nursery might be finding themselves having to quickly get from one to another to drop off in time, making the car the favoured option.”
Car usage was also around the same level in the peak hours between 3pm and 4pm and 5pm and 6pm as it was in March before the lockdown, the company said.
There have also been more midweek callouts to breakdowns, with the level “only a little” below those seen in the first few months of the year.
Government figures for the past few weeks showed car levels at around 90 per cent of normal capacity during the week. By contrast, on weekends the roads have been back at normal levels, or even exceeding them