While it’s not particularly common for a police officer to ask to search your car during a routine traffic stop, if the officer suspects that you may be intoxicated or involved in an illegal activity, the issue may come up. An individual’s protection from unlawful search and seizure is established, in Missouri, in Article 15 of the state constitution. Typically, a warrant is required to permit authorities to search private property. In the case of a traffic stop, though, police only need to establish probable cause for a search in order for it to be legal.
Probable cause can be generally defined as the accumulation of sufficient apparent facts that would lead a reasonably intelligent person to believe that the accused individual has committed a crime. Evidence that can establish probable cause can include the smell of alcohol, empty alcohol containers, empty plastic sandwich bags or similar containers used to store drugs, or even things like spraypaint cans or unbagged merchandise that has tags on it. Evidence for probable cause does not include expired documents, such as your license, registration, or insurance, even if the officer states that it does.
Rather than trying to establish for yourself whether an officer has probable cause to search your vehicle, you should always state to the officer that you do not consent to having your vehicle searched. This may not stop the officer from searching your car, regardless of whether probable cause is established. But, when you consent to a search, it immediately becomes legal, and any evidence found that can be used against you is much more difficult to refute. Protesting a search during a traffic stop can usually lead to a better outcome for you if you are charged with a crime, and in the best cases, may stop the search from happening entirely.