Chris Boardmans suggestion: A sign at a roundabout or where a road narrows that reads “motorists, give priority to cyclists” would have a massive impact on road safety by giving a clear instruction to both parties. It would cost little to implement and, in most cases, I doubt it would have much effect on traffic flow. In my opinion that simple signage, indicating a change of priority, would do more good for cyclists than 1,000 miles of cycle lanes that take me miles out of my way
It's simple and elegant, and I like it - although I'd maybe scratch the roundabout part, in case you get cyclists interpreting it as they ALWAYS have authority and just pull straight out onto it without looking - you know there will be at least one!
For pinch points and the like though, it's a really nice idea.