TexasCHLforum.com

I've been in the transportation safety field for over 20 years and this urban myth was around a lot longer than me. All DOT vehicles (>10,001 lbs) are covered by CFR 49 Parts 100 through 999. The first section 100-200 covers HAZMAT, second 300 - 399 covers the operation of motor vehicles, the last 400 - 999 cover required items (also known as the federal motor vehicle safety standards). In none of the sections are prohibitions against firearms mentioned. As for those operating just under intrastate authority, while most of the states have a few additions regarding medical requirements, age, starting size of vehicle, etc., all have adopted the Federal standards by reference as the governing standard. Here's a link to the FMCSA and TXDPS Commercial Vehicle Enforcement:

http://www.fmcsa.dot.gov/" onclick="window.open(this.href);return false;

http://www.txdps.state.tx.us/lw/index.htm" onclick="window.open(this.href);return false;

Hope this helps