If UK motorists plan to drive abroad after 29 March, they need to act soon or risk breaking the law.
That's because a no-deal Brexit would leave drivers needing to have proof of insurance known as a Green Card.
EU regulations will hit businesses and individuals. They will also apply to anyone driving across the Northern Ireland/Republic of Ireland border.
You need to order the card a month before you plan to travel, warned the Association of British Insurers.
Although European insurance authorities agreed to waive the need for Green Cards in the event of a no-deal Brexit in May 2018, it has not been confirmed by the European Commission.
It means Green Cards would be required under EU regulations as proof of insurance if the UK leaves the EU without a withdrawal deal.
The documents are supplied by insurers and anyone who drives without one may be breaking the law.
Meanwhile the government is still pressing for the European Commission to give the Green Card-waiver a green light.
A spokesperson from the Department for Transport said: "The UK meets all requirements to remain a part of the Green Card-free circulation zone when we leave the EU, and we urge the Commission to issue a decision which would ensure UK motorists can drive in the EU without a Green Card."
Who will be affected?
Among those affected will be:
*People who drive across the Northern Ireland/Republic of Ireland border.
*Anyone planning to take their vehicle to Europe, such as a family planning a holiday to France in the Easter holidays.
*Any freight company planning to transport goods into the EU after 29 March. Huw Evans, director general of the ABI, said:
"As it looks increasingly possible that a no-deal Brexit may happen, we want all insurance customers to know the facts about what this means for them."
However, he added: "Customers should always double-check their travel insurance policy meets their full needs."
If there is no deal with the EU, drivers may also need to get an International Driving Permit (IDP) to drive abroad.
RAC spokesperson Nicholas Lyes said: "There will be two different types of IDP that apply in EU states, so it is important that motorists heading abroad in the event of a no-deal Brexit check which is required. In cases where someone is driving to Spain via France, they would need both types of IDP."
From 1 February, the government will begin providing IDPs at 2,500 Post Offices across the UK.
How many people drive from the UK to Europe?
*The NI Department for the Economy suggests that there are approximately 110 million crossings between Northern Ireland and the Republic of Ireland each year. This includes cars, HGVs and buses/coaches.
*Eurotunnel Shuttle Services carried 1.6 million trucks and 2.6 million cars in 2017 (total number; both directions).
*According to official statistics, in 2017 there were 2.4 million HGVs traveling from Great Britain to Europe (excluding NI) and 370,000 HGVs traveling from Great Britain to Northern Ireland.