Which shape is used for stop signs?

The shape used for stop signs is the octagon. This distinctive eight-sided shape is specifically designated for stop signs to ensure they stand out to drivers. The octagonal design has been universally adopted to signal the need for vehicles to come to a complete stop at intersections where it is placed. The shape is easily recognizable and helps convey the message quickly, even from a distance or under poor visibility conditions.

Other shapes like diamond, oval, and rectangle are used for different types of traffic signs, serving purposes such as warning, guidance, or information, but the octagon remains unique to stop signs, which is crucial for road safety.