If you get pulled over by police and an officer thinks that you were driving under the influence of drugs, they may assume that there is evidence of that crime — drug paraphernalia or even the drugs themselves — in the car. If they want to search your vehicle, there are three basic ways to go about it.
Acting on suspicion
First off, an officer with reasonable suspicion of illegal activity can conduct a search. If they smell marijuana and that’s why they think you’re under the influence, for example, they may use that as justification for a search. They need to have a reason, though, and they may have to show that they did if the case gets to court.
Getting a warrant
Warrants for traffic stops are rare, compared to those for home searches, but they do exist. This can take time. The officer who conducted the stop may need to stay at the scene with you while someone else picks up the warrant for them.
Finally, an officer can always just ask for permission to conduct a search. If you do not want them to, you can say so, and that doesn’t mean you’re guilty of a crime. You can even refuse to answer if you’d like. That also doesn’t mean you’re guilty. You never have to give permission, but officers may ask for it in order to skip the first two reasons listed above.
If you do end up getting arrested, you must know what defense options you have, especially if you think the search was illegal.