Final answer:
The U.S. Supreme Court ruled in Arizona v. Gant (2009) that police officers cannot search a vehicle incident to an arrest if the arrestee is secured and poses no threat to officer safety, and if there is no reasonable possibility that evidence related to the arrest will be found in the vehicle.
Step-by-step explanation:
In the case of Arizona v. Gant (2009), the U.S. Supreme Court ruled that police officers cannot search a vehicle incident to an arrest if the arrestee is secured and poses no threat to officer safety, and if there is no reasonable possibility that evidence related to the arrest will be found in the vehicle. Therefore, in this case, the search of Rodney Gant's car after he was handcuffed and locked in the back of a patrol car was ruled to be unconstitutional.