Most of us have been there - the sudden jolt of adrenaline as we see the lights of a police vehicle behind us, signaling us to pull to the side of the road. We obey the directive and pull over, preparing for the inevitable encounter with the law enforcement officer. However, during a traffic stop, the police officer's power to investigate is not absolute. In fact, there are a number of important protections afforded to people who have been pulled over.
The law for vehicle searches rests on the side of the vehicle owner, not the police officers, who must have a valid reason or purpose for doing so. In fact, there are only 6 ways that officers can search a vehicle during a traffic stop. The first is the most obvious and legally supported - if the police have already obtained a valid search warrant in support of an investigation. However, search warrants are generally limited in scope, and it can be important to ensure the officer is staying within those limits. Not doing so can open up a legal challenge to any evidence collected.
Outside of a warrant, police can search if they obtain consent - but the driver can legally decline. They may also search the vehicle if a "plain sight" search reveals evidence of a crime, such as a bag of marijuana visible on the back seat of the car. In addition, police can perform a search incident to arrest, meaning if they have the necessary probable cause to arrest someone, they may search the vehicle. Police can also search if there is probable cause to suspect a crime. Finally, if "exigent circumstances" exist such as apparent evidence being destroyed, they can step in and perform a warrant-less search.
So, while the police have 6 avenues to perform a legal search, there are very real protections and limits on these legal searches. If a search is conducted illegally and it leads to drug charges, an experienced attorney may be able to successfully challenge the circumstances of the search and have evidence removed from consideration, possibly sinking a prosecutor's case. For this reason, knowing the law and mounting a vigorous defense could prove the difference between dismissed drug charges and a conviction.