I recently came across an interesting discussion on flyertalk.com regarding a permanent Border Patrol checkpoint located on I-10 in West Texas. Seems that the Border Patrol was going out of its way to harass car drivers with extensive questioning and drug sniffing dogs while just waving commercial truck drivers through without any questioning whatsoever.
Correct me if I’m wrong but it seems to me that commercial trucks are physically capable of transporting quite a bit more illicit traffic than a personal car. In fact, the last time I checked several personal cars can easily fit into the space occupied by a single commercial truck.