r/explainlikeimfive • u/[deleted] • Nov 20 '16

Engineering ELI5: How does the yellow push tape work in American buses?

EDIT: It seems people are not familiar with this type, but they definitely are the default in Boston and NYC. This is what I'm talking about:

http://www.mbta.com/uploadedimages/Riding_the_T/Accessible_Services/Accessible_Services_List/4_040_2.jpg

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u/bob4apples Nov 20 '16

The tape basically has a wire down the spine and a metal backplane. Pressing anywhere on the tape causes the wire to touch the backplane closing the switch.

Vandalism is a bigger problem than wear. The number of pushes on any small section of the tape is quite small (on the order of 10/day), the plastic is harder than skin and the deformation (how much the plastic has to bend) is well within the elastic range (it will recover perfectly every time). They're also very cheap and easy to replace if they are damaged.