When it comes to proactive policing, particularly in the contraband interdiction realm, the most successful officers stay alert for “curiosity ticklers” – things that are out of the ordinary and may tip observant cops off to the fact that something may be hinky. Several of those ticklers are related to unnatural behavior while driving. Here are a few:

Stay alert for a driver who anxiously and repeatedly looks in the rearview mirror or repositions it to get a better look at you when you pull behind them. Some of that is natural, of course, but watch for an excessive amount of focus on you in the mirror. Also, watch for passengers repeatedly glancing at you or turning their heads to get a better look at you when your squad is positioned around the vehicle. Also, keep an eye out for drifting caused by a driver focusing more on you than the road.

Top interdiction experts have noted that nervous drivers will very often sit up very rigidly when they spot your unit. They’ll grip the steering wheel for dear life and meticulously following every traffic law. Some will slow down or change lanes unnecessarily in an effort to avoid speeding and in the hopes that you drive by them. Also, keep an eye out for anxious behavior inside the vehicle; things that can surface anywhere as indicators of nervousness—things like excessively stroking their hair or repeated stretching their arms over the seats or repositioning themselves.

Many interdiction experts cite what they call “The No Look Rule” as one of the most powerful indicators of trouble. This involves someone absolutely refusing to look over at you when you pull up next to them at a light or pace next to them on the highway. Most everyone will glance over at traffic next to them at some point, if even briefly, especially a police vehicle. If you’re trying to hide something, that may be the last thing you want to do…kind of like thinking, “If I don’t look over, they won’t notice me. They’ll just go away”

Some officers intent on determining whether a suspicious driver is a no-looker will pull up just beyond the vehicle they’re observing so there’s no doubt they saw the unit, then slow down and drive beside them. This is where you can draw out a series of nervous responses like those just mentioned; stiffen up, gripping the wheel, desperately trying to maintain the speed limit, staring rigidly ahead and never even glancing over or even overtly looking the other way. One officer skilled at interdiction and a believer in The No Look Rule will tap his horn or yell out, “Hey, hey over here” when pulled up next to a vehicle he’s focusing on in an attempt to attract the occupants’ attention. If they’re consciously avoiding making any eye contact whatsoever, it will be pretty obvious in situations like that.