Is Cannabis Odor a Reasonable Cause for Cops to Search a Car?

Is Cannabis Odor a Reasonable Cause for Cops to Search a Car?

Published on 4/12/22

What happens if you get pulled over and there's weed in your car? Does it matter what state you're in or where you got it? The short answer: yes. Some states, like Colorado and Illinois, have passed laws stating that cannabis smell is no longer a reasonable cause for cops to search a vehicle, but that isn't the case everywhere. Let's dive into the laws, regulations, and consequences of driving with cannabis. 

Where's Weed does not condone driving while under the influence of marijuana. No matter what state you're in or how much you've consumed, it is dangerous and illegal to drive while under the influence of any substance that renders you incapable of safely operating a motor vehicle. Nor does Where's Weed condone the illegal transportation of cannabis across state lines or the possession of cannabis in states where it is illegal. 

The "In Plain Smell" Law

Have you ever heard of the "In Plain Sight" law? If an officer sees something suspicious, they are allowed to instigate a search and seizure without any cause other than claiming that they could see something illegal or suspicious. The "in plain smell" law follows the same logic. If an officer claims to have smelled marijuana, they can conduct a search and seizure without a warrant. Additionally, the United States Supreme Court has ruled that a police officer's motivation for pulling someone over is irrelevant so long as they have a legitimate reason for pulling them over in the first place. This type of law often gives personal bias and prejudice legitimacy. For example, an officer can pull someone over with racist motivation and claim to have smelled marijuana. If the officer finds marijuana, it is often seen in the eyes of the law to be a legal search and seizure operation. This likely goes a long way in explaining why arrest rates for marijuana possession are so much higher amongst minorities in America, specifically black men. According to the ACLU, black people are 3.6x more likely to be arrested for marijuana possession than white people.

How Cannabis Smells Work


These laws are especially concerning since science has proven that it's not all that easy to smell cannabis. We've all been driving down the street and gotten a big whiff of weed from the car next to us, but that's likely because that person is actively smoking in their car or the marijuana is very poorly stored. Recent research has shown that marijuana in plastic baggies or out in the open is very identifiable. Cannabis is incredibly potent because of its high amounts of terpenes, oils secreted from cannabis flower responsible for its aroma and flavor. While cannabis terpenes are very noticeable, there are easy ways to ensure that no one can smell your stash. The same study showed that mason jars, glass containers, and doubly vacuum-sealed plastic nearly irradicate the chances of marijuana being identified via smell.

Cannabis Smell: Reasonable Cause Precedent

Fortunately, it seems that the "In Plain Smell" logic is beginning to lose favor. There have been several landmark cases over the last few years that give precedent for not allowing marijuana odor as probable cause. A recent case in Maryland, wherein a man was observed smoking a marijuana cigarette in his car and then searched and arrested for cocaine possession, was overturned because Maryland's laws allow possession of up to 10 grams. Since the observation of marijuana odor didn't indicate the individual had more than 10 grams of marijuana in his possession, the search and seizure was deemed unlawful. The ruling has now set the legal precedent in Maryland that marijuana odor is no longer a reasonable cause for search and seizure. 

Of course, these cases are being contested on various levels. In Illinois, a man was recently arrested when an officer smelled marijuana and found two grams in his possession after pulling him over for speeding. The man fought the misdemeanor charge and won, spurring a ruling that makes it so that marijuana odor no longer gives probable cause for an unwarranted search in Illinois. Local officers claim that this ruling will get in the way of charging people who have recently smoked and are driving under the influence. Despite these objections, the verdict still stands. 

State by State: Cannabis & Driving Laws


There are now 18 states that have legalized recreational marijuana (not including South Dakota due to the current lawsuit holding up approval). Along with not driving while under the influence, not smoking in your vehicle, not transporting across state lines, and properly storing your cannabis in an odor-proof container, another way to stay safe while transporting cannabis is to follow your state's specific transportation laws. Here are the current laws for several of those 18 states where recreational weed is allowed.


Up to 1 ounce of marijuana can be transported so long as it is sealed or contained and locked in a safe and secure storage compartment within the vehicle. There is currently no limit to the amount of cannabis that can be transferred between licensed marijuana businesses at once.


Up to 28.5 grams of marijuana can be legally transported so long as it is in a sealed container (although medical patients are given slightly more leeway). Because of California's open container laws, your cannabis must be sealed away. 


Up to 2 ounces of marijuana can be legally transported so long as it is in a sealed container. Like in California, Colorado's open container laws make it so that all cannabis must be sealed away.


Up to 30 grams of marijuana can be legally transported so long as it's in a sealed, odor-proof, child-proof container that is inaccessible from the driver's seat.


Up to 1 ounce of marijuana can be legally transported so long as it's in a sealed container away from the driver and any passengers under the age of 18. 


Up to 1 ounce of marijuana can be legally transported so long as it's in a sealed package and is not opened during transport. Live plants may also be transported so long as they are fully enclosed in the trunk or a secured area within the vehicle.

What are your thoughts on the cannabis laws where you live? Let us know in the comments below!

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