We have anti-climb roller spikes here - I imagine raccoons are agile enough to get through barbed wire and fence spikes - I'm thinking roller spikes would be a lot more difficult - they are as they are described, spikes which rotate.
Britain is on a high raccoon alert - there have been sightings of raccoons in England and other parts of the UK - they are reported to be escapees from zoos and people having had them as pets - the worry is that they will breed and establish themselves over here as is what happened in Germany - the "lost" pets reported so far have been singular, so unable to breed unless they meet another opposite sex escapee, so is less likely however it has not yet been established whether or not the zoo escapees are in pairs or groups or not. I don't like harming animals but I have to say if they ever reach my area I will be setting poison traps for them and I'd get every deterrent I could find, including rolling spikes!