You may have never paid much attention to the small bumps that are on the pavement at a crossing.
You are more than likely aware that they have been placed there to help visually impaired people know that they are at a crossing or platform.
What you might not have known is that many of the different bumps and surfaces actually have specific purposes to help the visually impaired.
These range from the shape of the bumps to their various placements in different locations.
Dr Amy Kavanagh explained their various uses in an informative and viral twitter thread that will make you think twice about the next time you cross the road, how to navigate them, and how they are maintained.