Stair Channels are a common feature in the Netherlands and other bike-friendly countries. So why don’t we have them in the US?
Actually, we do. The BART system has implemented them at several stations, most recently the Ashby BART station as part of a station retrofit. Chicago has them also. But those efforts, while well-meaning, have been underwhelming. American channels are tiny and situated too close to the wall.
The problem is planning code and ADA leaves little room to design a proper stair channel. Make the ramp stick too far out from the wall, and the regulations say you’ve created a “tripping hazard”. Not wanting lawsuits, transit agencies did the best they could under the circumstances.