Sequential indicators: UK vs US vs Germany

Sequential indicators were federally prohibited in the US until a 2013 rule change, which is a useful reminder that these rules move. All three markets now permit them with approval, and all three describe the same trap: the retrofit module that makes an ordinary indicator sweep. The lamp was approved as a flashing indicator, not a scrolling one, so a module that changes its behaviour puts it outside its approval even though nothing physical was replaced. Germany states this most precisely, requiring that the approval expressly cover sequential operation and that the sweep run inside to outside in the direction of travel. The colour and flash-rate requirements are effectively identical across all three, amber at the front and a steady rate in the standard band.