I was at Euston station earlier today and noticed looking at the last set of escalators coming up into the main station from the underground, that on the left of each step were 2 polished stripes parallel with the direction of travel running from the outer edge about 3 quarters of the way to the inner edge.

It seems to me that it is probably due to people scuffing their feet along the step as they walk up the escalator. It just amazed me that it could make such a difference, but I suppose there must be hundreds of people using that escalator every day.

I checked the escalators at London Bridge on the way back, but there weren't any stripes, but then I'd expect London Bridge has slightly fewer people through it day (still a considerable number though), so now I'm wondering what the minimum requirements are for the stripes to appear.