Damn. I've been curious what the deal is with the rubber lego knob coverings on sidewalk ramps and here it is. I mostly notice because they're such hell for skateboarding, so it never occurred to me they'd be an ADA thing as I assume they're equally hard to navigate in a wheelchair, but apparently the idea is to provide a tactile warning that the street is nearby for people with vision impairments.

>I mostly notice because they're such hell for skateboarding, so it never occurred to me they'd be an ADA thing

"Be hell for skateboarding" wasn't likely considered a bonus by the disability people because it would rally "those sort of people" to their (otherwise legitimate) cause.