Every vehicle search in a Harris County case falls into one of five boxes. Four of them are the officer's to justify. One is yours to give or withhold. Brian Foley maps them in this video.
1. Consent
The officer asks; you say yes. The search is lawful regardless of what the officer knew or suspected. Consent must be voluntary, and it can be limited ("you can look in the back seat") or withdrawn. It is refused by saying, clearly, "I do not consent to a search." See refusing a search.
2. Probable cause — the automobile exception
Specific facts creating a fair probability that contraband is in the car: plain-view contraband, an admission, a reliable K-9 alert, odor (contested). The search may extend anywhere the item could be, including the trunk and containers. See probable cause to search a car.
3. Search incident to arrest
After a lawful custodial arrest, officers may search the arrestee's person, and — under Arizona v. Gant — the passenger compartment only if the arrestee could reach it or evidence of the arrest offense might be inside. A traffic-offense arrest rarely satisfies Gant. See ticket arrests and searches.
4. Inventory
If the car is lawfully impounded, officers may inventory its contents under a standardized policy. The impound decision and the policy compliance are both challengeable. See inventory searches.
5. Warrant
A magistrate finds probable cause on a sworn affidavit. Warrants for vehicles are uncommon at roadside but frequent in investigations, and the affidavit is reviewed for errors and omissions.
The one you control
Exceptions 2 through 5 are litigated at a suppression hearing where the officer testifies, the video is played, and the State bears the burden. Exception 1 skips all of it. Whatever else happens at a stop, do not consent. Brian Foley and Luis Baez argued these hearings for the State and now argue them for the defense. Call or text (713) 703-1718.