This street is Exchange Way, according to the City of Webster Groves GIS map, and Google Maps - the street labeled "Exchange Way" just south of here, is also labeled that way in Webster Groves GIS data (not in Google Maps) but it is entirely within the property of the building materials company, so it seems unlikely to be correct. 
https://webstergroves.maps.arcgis.com/apps/View/index.html?appid=284551609b944b39b65246c6cc5c786a&extent=-90.4074,38.5556,-90.2754,38.6199 

There's also a sign visible in Google Street view that shows that this more northern street is Exchange Way: https://goo.gl/maps/svpqii6szG8noRFHA 