Holidaymakers travelling through Dover are being urged to stock up on vital supplies following severe delays last weekend.
The Kent port is expected to be busy again over the coming days as travellers arrive to cross the Channel.
Tailbacks reached 12 miles last weekend and some people were forced to wait for 15 hours on gridlocked roads.
Police said the disruption was down to the vast volume of holiday traffic coupled with heightened security checks by French officials in the wake of terror attacks.
The Port of Dover, which manages the port, said it is not expecting the extent of the delays to be repeated this weekend.
But Kent Police issued a statement which read: "Motorists planning to travel towards Dover this weekend are being advised to take plenty of food and water before setting off."
It went on: "Those planning to use the roads towards Dover are being urged to check the latest travel updates from Highways England and their travel operator and take adequate provisions and any medication in case there is disruption."
The force added that major delays could have a knock-on effect on surrounding areas and called for people living in the south-east of Kent to "plan ahead".
The Port of Dover told travellers: "Whilst we do not anticipate further severe delays, this remains our busiest time of the year and we do expect increased traffic volumes as the holiday season continues to get under way.
"Currently, roads to the port remain clear and free flowing and there are no queues inside the port."
French highway authorities are warning that heavy congestion is set to hit main routes throughout the country on so-called Black Saturday, when there is a crossover between holidaymakers heading home and those just beginning their breaks.
Motorists are being advised to delay their journeys until Sunday.
A second Black Saturday is expected on August 6.
RAC European Breakdown spokesman Rod Dennis said he hoped lessons have been learned "after the chaos of last weekend".
He went on: "If for any reason there are tailbacks on the M20 and other routes to the south coast we hope the authorities will do a better job of communicating information, and have effective contingency plans in place to look after motorists and their passengers."