Probably on a private road on private land with the landowner's permission. Maybe also on a public road in a serious emergency, although I expect that there would be a very big "please explain" as a consequence.
I did land once on a public road in a remote location over 30 years ago, after first surveying it for miles in both directions to ensure that no vehicle or person would be able to see it. I remained on the ground for a couple of minutes only.
Last edited by Colibri49; 17th Dec 2017 at 23:02.