I believe that the roundabout depicted at this marker is out-of-date. There used to be a mini-roundabout here, but as part of the interchange project in this area, the roundabout was rebuilt to be centered slightly to the SSE of this marker.

A schematic of the new roundabout, which includes a bypass lane from westbound US 54 to Route W, is available (see Project Displays, Aerial View):

https://www.modot.org/Miller54Interchange

The Public GPS Traces suggest the new roundabout's position/configuration.