This plan for the M20 is the first major preparation which has been made for a no-deal Brexit, and there's a reason. Despite setting deadline after deadline, each one announced with a certainty that Brexit will definitely happen this time, not much seems to have been done to prepare the country for Brexit, whether there’s a deal or not. While some members of the public have been preparing themselves for Brexit, the government has not had many preparations set in stone for a no-deal Brexit.
When it comes to preparing for Brexit, some people are doing more than the politicians
The lack of government planning and preparation for Brexit is almost indicative of the fact that politicians have no idea what they are doing about Brexit. This is further emphasised by the endless months of making plans and deals only to have both rejected while Theresa May was Prime Minister, and again with the most recent deadline change from the end of October to January 2020 for the UK to leave the EU. As a result, the general public are becoming less patient and more scared over the uncertainty and delay of Brexit, which the government has not addressed properly. People are making their own, much smaller scale preparations for Brexit: some are doing more than the politicians who are meant to be running the country.
Jamie Hampton's view on no-deal preparations, and the role business can play, can be found here: https://www.thecourieronline.co.uk/no-deal-brexit-preparations-it-takes-two-to-tango/