Troublespots are likely to include the M4 eastbound, the M3 and M5 northbound, the whole of the M25 and the M6 between junctions 20-21a and 28-9.
A spokeswoman for AA Roadwatch said: "We think tomorrow evening will bear the brunt of it.
"We're saying to people that it might be advisable to leave at lunchtime or mid-morning so the traffic is staggered."
The AA said traffic problems yesterday centred on car boot sales and Sunday markets with some congestion on roads leading to the Yorkshire coast.
Airports said they were also expecting a busy day today after a weekend of heavy travel.
Both Gatwick and Heathrow said the number of people taking off last week had been up on last year.
A spokeswoman at Heath-row said the most popular destinations had been Florida, the Far East and the Eastern Mediterranean. "It makes a change from Dublin, Paris and Amsterdam," she said.Reuse content