osmlab
Improbable speed limits on roundabouts
This roundabout and its approaches were tagged with maxspeed=55 mph until I removed that tag in changeset 53,605,859. It’s highly improbable that a driver would be able to round a 100-foot-wide roundabout at anywhere near 55 mph. A typical roundabout of this size would have a speed limit of 20–25 mph (30–40 km/h). Even a 300-foot-wide (91 m), multilane roundabout would only allow 30 mph (50 km/h) at most.
It looks like this roundabout wound up with the improbable maxspeed tag because a mapper simply added a roundabout at an intersection between two roads, ignoring the existing maxspeed tag on one of the roads. In the Midwestern U.S., it’s becoming increasingly common for blinking four-way stops along rural, two-lane roads (which typically have a speed limit of 55 mph) to be replaced by roundabouts. A linter can catch these copy-pasta situations where the mapper ignores a preexisting maxspeed tag.
/cc @Rub21
