Places that have a huge amount of pedestrian traffic put a lot of planning into the engineering and design of sidewalks and streets. The most obvious evidence of this are crosswalks, signals, and street lights.

For those of you who aren’t habitual jaywalkers, you may have noticed something else on the sidewalk. You may have noticed something different at busy crosswalks or intersections. Those bumps on the sidewalk seen at intersections are part of a system called tactile paving.

Designed to help visually impaired and blind people safely navigate walking surfaces, each set of markings has a specific purpose. While walking, the patterns are felt by walking canes or detected by the feet. In this video from by Tom Scott, with an assist from the UK’s Royal National Institute of Blind People, these patterns are explained.

First put to use by Japan in the 1960s, tactile paving was introduced to Europe, Australia, and the U.S. by the 1990s. Now it’s used all over the world, with each country having its own system. Universally, color coded paving helps those who have partial sight to understand warnings or directions.

Tom shows us that in the UK, the dots at the curb mean there’s a crosswalk. When it’s red, that indicates the crosswalk has a mechanical traffic control attached to it. Where the knobby grid sits or drops closer to the street serves as a warning that the street is right next to it, and that a wheelchair ramp exists for crossing.

He further highlights that offset dots are used at railway platforms. Spaced differently than crosswalk grids, they’re used to steer people away from the edge and tracks below. Others like lozenge-shaped markings are used on the edges of walkways to signal rapid transit platforms (i.e. buses). Follow Tom through the video as he outlines the other types of patterns.

One of the things mentioned by Richard Holmes of RNIB is that there isn’t always consistency with the tactile paving. Problems include grids being covered by grates or concrete, or lack of distinct color contrasting for the partially impaired. What good is gray on gray pavement coloring for those who have partial sight? Such design mistakes are hazards that can cause someone to end up in the road.

Because of the scale and complexity of the system, Tom states that standardization can sometimes be a challenge. Here in the US, tactile paving is required by the Americans with Disabilities Act (ADA) in certain locations. In addition to some of the areas they’re placed in the UK, you’ll also find them here near reflecting pools.

Click on the video to find out more about how tactile paving is used, and some of the challenges faced by those with limited or no vision. Not all cities have it, but many districts are creating environments that are more accessible to the disabled community. It’s important that everyone can get around safely.

Did you already know what these dots were for? Where are some places you’ve seen tactile paving not mentioned here? Tell us in the comments!