Less is definitely a good shout. There's a residential area for the elderly near where I live, which is a good half a mile from the nearest road. On said nearest road there are THREE signs, showing elderly people near by. It's not as if they wander aimless around and into the road like cattle.
There's also a stretch of the A30 as you get deeper into Kernow, which goes from a dual carriage way into a single carriageway. It's a notorious bottle neck and anyone who drives/rides it regularly knows to avoid it on a Friday/Saturday in the summer (changeover day). The highways agency have very thoughfully added a mobile sign which reads 'Delays Ahead'. This is conveniently placed about 2 miles after the tailbacks normally start, cheerfully reminding you about the jam you're already sat in.
(Unless you're on a bike, which I usually am

).