Based on my familiarity with law enforcement and the frequent arrests of drug runners passing through our county on I-80, I suspect the "swerving" was probably pretty minor and similar to the occasional drifts you or I might make when we drive our RVs (particularly when we were newbies). What often happens is that the state troopers or local LE get a tip that a certain vehicle may be headed that way carrying a large quantity of contraband. They then keep a lookout and tail the vehicle when it enters the jurisdiction. When the vehicle commits any type of minor violation, such as crossing the center line, drifting onto the shoulder, following too close, etc., the cop has cause to make a traffic stop. In the course of the stop, he will ask for consent to search the vehicle. If consent is refused, a dog may be walked around the vehicle and then if it alerts, the officer has probable cause for a search.
Just speculation, but most of the seemingly "random" traffic stops that result in large drug busts aren't as random as they seem. Please note that I'm not saying I have a problem with this technique (some do) or trying to start a debate over drug policy; just trying to suggest that there may be more to the story. Perhaps Marty (SargeW) or one of our other law enforcement personnel have some input.
