What do officers need in order to initiate a stop of a motor vehicle? It is commonly known that they need to observe a car committing a traffic violation, or driving in a suspicious manner. Without these observations, a stop could be considered as violating the Fourth Amendment's protections against unreasonable searches and seizures.
A case emanating from the state of California could change this notion. The U.S. Supreme Court will hear a case where a traffic stop (and subsequent arrest) is being challenged because the arresting officers did not actually see the car driving recklessly before stopping it.
Instead, dispatchers for the California Highway Patrol (CHP) received an anonymous tip that a silver Ford F150 truck was driving erratically, and had run another driver off the road. They communicated the description to officers in the vicinity, who saw the truck and stopped it. When the officers approached the vehicle, they smelled marijuana, which they claim gave them probable cause to search the truck. They found several bags of the drug, and arrested the driver and his passenger on suspicion of drug possession.
The two arrestees pled guilty, then appealed; claiming that the stop and subsequent arrest violated their Fourth Amendment rights since the officers did not observe the alleged violations first hand, and because anonymous tips are usually insufficient to search or detain someone.
The case may have additional implications for police observations such as seatbelt violations, cell phone infractions and red light violations. It is worth noting that the Court previously declined to hear a similar case from Virginia after the state supreme court reversed a conviction where an anonymous tip alerted police to a drunk driver.
Source: DenverPost.com, Court: Is anonymous tip enough for traffic stop?, October 1, 2013