Bicycle Austin forum

Hey guys,
 
   I'm trying to find out if ALL bike lanes across Texas are protected from motor vehicle encroachment. We're having issues here at College Station with Transportation Services (Bus system at Texas A&M) driving in bike lanes at intersections and to take right-hand turns. Of course, this is dangerous and I thought it was illegal. However, I am having difficulty actually citing the law that says motor vehicles cannot drive in this lane. I saw the traffic laws posted on this website for Austin but nothing in regards to an official state law. Does anyone have any suggestions? Thoughts? A link? A citation of Texas State Law?
Thanks guys!