Washington has a state constitution

In State v. Tibbles, No. 80308-1 (Wash. Aug. 5, 2010), the Washington Supreme Court held that the exigent circumstances doctrine didn't apply to a warrantless car search under its state constitution. The circumstances routinely occur in Kansas--officers stop a car and smell marijuana. Courts, including the Tibbles Court, hold that this constitutes probable cause. But the remaining question is whether there are exigent circumstances to dispense with the warrant requirement:

Considering the relevant factors in determining an exigency, the State has not shown that exigent circumstances justified the warrantless search of Tibbles's car. The situation in this case stands in sharp contrast to other situations in which we have held exigent circumstances to exist. In Patterson, we concluded that exigent circumstances justified entry into a parked vehicle where a burglary had very recently been committed, the suspect was likely in the immediate vicinity of the vehicle because the officers discovered the vehicle a mere five minutes after the robbery, information in the automobile could help identify and locate the suspect, and a delay in searching the vehicle could have allowed the suspect to flee the area. Similarly, we found exigencies in Smith where there was a tanker truck filled with 1,000 gallons of a dangerous chemical parked next to a house, a rifle had been seen in the house, the rifle went missing, and the two known occupants of the house did not possess the rifle. 

On the stipulated facts in this case, the State has not shown any need for particular haste. The suspect was not fleeing, nor has there been any showing that he presented a risk of flight. While there was probable cause that evidence of contraband existed in the vehicle, Tibbles was outside the vehicle when Trooper Larsen searched it and the State has not established that the destruction of evidence was imminent. Additionally, the State has not established that obtaining a warrant was otherwise impracticable. For example, we do not know whether Larsen could have used a cell phone or radio to procure a telephonic warrant or whether he could have called backup to secure the scene while Larsen went to procure a warrant. The record contains no evidence of what Larsen would have had to do to procure a warrant at the time of the search. 

With regard to safety concerns, the stipulated facts do not establish that Trooper Larsen felt he or anyone else was in danger as a result of Tibbles's actions. Tibbles was not stopped on suspicion of impaired driving, but rather for a defective taillight. Tibbles was alone, was compliant with the trooper's requests, and moreover, was released rather than arrested and allowed to drive away even after Trooper Larsen searched the car and seized the marijuana and drug paraphernalia. It is the State's burden to establish that one of the exceptions to the warrant requirement applies. In the case of hot pursuit or similar situations presenting a risk to officer safety, the State's burden can be met by establishing the immediacy of the risk of flight or risk of harm. The facts, as presented here, do not implicate these concerns, nor has the State attempted to show why it was impracticable for Trooper Larsen to obtain a warrant before conducting his search. To find exigent circumstances based on these bare facts would set the stage for the exigent circumstances exception to swallow the general warrant requirement. It would give the erroneous impression that an exigency may be based on little more than a late-night stop for defective equipment, an officer working alone, and circumstances indicating possible drug possession. This very likely describes any number of encounters between law enforcement and private citizens that occur everyday.

"Any number of encounters between law enforcement and private citizens that occur everyday."