If police need to have probable cause to even start searching for evidence of a crime, what factors come into play in order for them to pull you over for operating under the influence (OUI)?
In some cases, it's pretty clear that a police officer has probable cause to believe a crime has been committed when he or she observes a person driving drunk and later, conducts an OUI investigation that includes field sobriety testing. If an officer watches someone stumble out of a bar and take several minutes to key into their car before turning it on, not many will doubt that the officer had probable cause to believe that the driver was attempting to operate his vehicle under the influence for the purpose of arrest.
When a cop is patrolling on the highway and sees a car driving erratically, how much swerving does it take before there's probable cause to stop it? Good question but wrong terminology. In legal parlance, a police officer needs LESS than probable cause to pull a car over. Instead, the officer needs a reasonable articulable suspicion (RAS) to stop a car for a traffic infraction or to believe a crime may have been committed, IE, like DUI. A car crossing all three lanes of a highway or swerving repeatedly within its lane obviously gives police RAS to pull it over, however, a car never contacting the lane markers, does not give the officer RAS to stop the car. In Maine, probable cause is the standard that gives the officer grounds to effectuate an arrest. On the other hand, reasonable articulable suspicion is the standard that allows an officer to stop a car and/or expand the scope of the investigation into a full-fledged DUI investigation. The basis for the officer's suspicion must be both reasonable and articulable and cannot be based on a mere hunch or guess work.
Two cases from the Tennessee Supreme Court highlight the legal significance of RAS. In one case, a driver crossed the fog line once, and touched it two more times with both of her passenger-side tires. A cop pulled her over, and during the traffic stop found that the driver was intoxicated. Similarly, in the other case, the driver crossed the center line once, got pulled over, and was arrested for drunk driving. All of the evidence used to convict the two drivers came during the traffic stop. If the police officer didn't have enough reasonable articulable suspicion to pull the driver over, the traffic stop never would have happened, the evidence of their OUI would never have been gathered, and neither driver would have been convicted.
However, the Supreme Court of Tennessee decided that this small amount of swerving had been enough to give the officers RAS to pull the drivers over, and agreed that their conviction should stand.
Think about that. When's the last time you were driving and your wheels touched one of the lines? It probably wasn't too long ago, because that sort of thing happens pretty frequently, even to the best of drivers. Now imagine being pulled over by the police and told to take a breathalyzer test every time your wheels crossed a line on the road. This is how traffic stops happen, now, in Tennessee and all across the country.
If you're facing an OUI charge in Maine, and the police officer pulled you over for something as common as touching a lane marker with your tire, challenging your charge in court is hugely important. If you can show that the police officer did not have a reasonable articulable suspicion to pull you over and that the search that gathered all the evidence against you was unconstitutional, your case should be dismissed.