Neighbour Parking

I live in a housing estate which has a busy road running thru it, my next door neighbours house owns four cars and two of them are constantly parked on the public roadway outside my driveway at either side of my entrance gate, these block my view of traffic on the road as I enter or leave my driveway. While I accept that nobody has the right to exclusively park outside their driveway on the public road, I feel that these cars are obstructing my view and are a danger, I have brought this up with my neighbour but to no satisfaction, I feel they should have considered where they were going to park four cars before they bought them, any advice please? There are no road markings and the neighbour is a difficult person to deal with.