A man in his 50s from Herne Bay died on Monday after an accident on the A299 Thanet Way near Whitstable.
Police were called at about 6pm after reports of a one vehicle collision London-bound, just before Chestfield tunnels.
A black Citroen Xsara coupe was travelling in the outside lane when it crossed the inside lane and landed on its roof in a drainage ditch.
Kent Fire and Rescue Service and South East Coast Ambulance Service attended.
The man was confirmed dead at the scene. No one else was in the vehicle and no other injuries were reported.
Both lanes were closed for emergency services to deal with the incident. The outside lane was reopened at about 7.45pm and the road was fully reopened at about 12.30am.
Police are appealing for witnesses.
They are keen to speak to the driver of a light coloured BMW or similar looking vehicle who was in the area at the time of the collision and may be an important witness.
Anyone with any information should contact the serious collision investigation unit on 01622 798538.
Don't miss out, subscribe today. Keep up to date with our newsletters.
A guide for your future. For year 11 students in Kent and Medway. Click here for the e-edition.
Education, Training & Childcare is a special supplement published by KM Media Group four times a year. Click here for latest e-edition.
Get the latest food and drink news, recipes from some of the nation's top chefs plus updates from Kent's vineyards and breweries.
Search in your local area to find your perfect partner in Kent, with FreshStart Dating! PLUS, register for free!.
Find out what's going on in the garden, with Kent expert Lucy Hewett's weekly update.
Buy pictures that you've seen in a KM newspaper, or send in a picture and we will place it on our photo sales website so that you can purchase a super, unique gift.