There is a gate at this point, and the roads to the south are part of the private property of the building materials companies. This is evident in the City of Webster Groves property map, which shows that Breckenridge Industrial Court ends at the location of this note:  https://webstergroves.maps.arcgis.com/apps/View/index.html?appid=284551609b944b39b65246c6cc5c786a&extent=-90.4074,38.5556,-90.2754,38.6199