What should you do if it’s raining and you’re following this lorry on a motorway?

The usual two-second time gap increases to four seconds when the roads are wet. If you stay well back, you’ll
• be able to see past the vehicle
• be out of the spray thrown up by the lorry’s tyres
• give yourself more time to stop if the need arises
• increase your chances of being seen by the lorry driver.