Millions are facing traffic misery on Monday morning as holiday makers head home and children gear up for the return to school, figures suggest.
The morning rush hour is expected to bring the worst delays and lengthy traffic jams.
And the hold-ups are set to continue into the afternoon on what is predicted to be one of the busiest days on the roads.
Data gathered by road information service TomTom HD Traffic showed there were 1,087 miles of delays across the country between 6am and 9am on last year's "back to school" Monday.
This compares with just 385 miles of congestion on a typical Monday morning in August.
And heavy traffic is expected to become the theme of the day.
Between 9am and 1pm on the same Monday last year, there were 869 miles of delays.
On Monday September 7 last year, there were also 297 more traffic incidents reported than on an average day.
At 8.30am, there were 578 separate accidents or break-downs causing rush hour delays compared with only 281 incidents at the same time in mid-August.
A spokesman for TomTom said: "The traffic tomorrow is likely to be twice as bad as it would be on a normal Monday, and in the morning it will be nearly three times as bad when there could be long delays on the roads."