In my work guiding people accused of DUI in Idaho through the legal process, I am often asked about whether the legal basis for a traffic stop was proper. A traffic stop is a “seizure” for the purposes of the 4th Amendment, so police need probable cause of a law violation prior to stopping you. If there is no legal basis for a traffic stop, the evidence obtained following that stop is subject to suppression. Meaning, the results of the FSTs, the breathalyzer results, and any incriminating statements made cannot be used in a trial.
A violation of the traffic laws provides probable cause to believe an infraction has been committed and the driver of the vehicle committed it. In other words, violating a traffic law is a basis for a traffic stop.
I was scrolling through my Twitter feed the other day and came across this image:
This diagram is spot-on and represents one driving law I see violated daily.
When making a turn, you must turn into the lane closest to you. Meaning, if you turn right onto a 2-lane road, you must turn from the right-most lane (or designated turn lane) intothe right-most lane. If you turn left, you must turn from the left-most lane (or designated turn lane) intothe left-most lane. If you don't do this, you provide law enforcement with probable cause to stop you.
Following the traffic laws will save you a potential “visit” by law enforcement in the form of being pulled over. It will take your time, expose you to stress, and, potentially to further testing for impairment. Knowing and following the rules of the road not only keeps you from being pulled over, it also keeps our roads and highways safe.