What does the road sign with a blue background, red circle and red x mean?
A round sign outlined in red with a single red line diagonally across it means no waiting.
Any sign with a red circle around it tends to be prohibitive; no right turn, no left turn, no U-turns.
Signs with a blue circle around them are usually positive and indicate one-way traffic or that you should turn left turn ahead.
A London-based graphic designer recently won the £1000 first prize in the InTandem competition sponsored by the UK's first driving feedback service, How’s My Driving, by designing a new sign for display on the back of HGVs that reminds cyclists that it is dangerous to ride on their left side.