Drain on enbankment backing up and flooding my property

Outside my property Butterbread Barn EX6 6JD is a drain on the enbankment to the A30 just over the wall between my drive and the crash barrier - all the ditches/drains on the road drain to a brick ditch type drain - the pipes coming into this (think there is 3) are larger than the pipe that drains somewhere onto the enbankment and does not run away fast enough - this causes this structure to overflow and discharge the water and other contaminated products from the road (diesel, silt, debris) onto my property and is making my drive wet and unstable. Devon highways deal with the ditches and drains but as this forms part of the A30 enbankment they say that you have to deal with the issue