Stop signs in general are pretty hard to miss – you’ve got a bright red octagon shaped reflective sign that says ‘STOP’. Yet sometimes, people miss the sign.
In Sydney, Australia, it’s becoming a particularly bad problem around truck drivers entering tunnels when they shouldn’t be. They’ve come up with a rather neat idea to get inattentive truck drivers to stop though: water.
When a truck is approaching a tunnel that is too small for its size, there are a sequence of stop signs that light up. If the truck fails to do so, in a last ditch effort, a projection of a stop sign against a stream of water will appear, covering the entrance entirely. This makes the sign almost impossible to miss, and in the rare instance that a driver does not stop, then they would simply pass through the water stream.
Watch the video to see how it works.