In order for a law enforcement officer to make a lawful and thus legal stop of a motorist, the officer must have witnessed that a crime (even just an infraction) was committed in the officer’s presence. The law requires that there be “a reasonable suspicion that some law was violated.” This violation of the law could be something as trivial as speeding in excess of 1 mile over the speed limit or something as reckless as driving into oncoming traffic. What is required in both instances to effectuate a valid lawful traffic stop is ANY reasonable suspicion that a law (traffic) was violated. The seminal case stating this “reasonable suspicion standard” was first mentioned in the Landmark United States Supreme Court case of Terry v. Ohio. What is important to know is that this “reasonable suspicion standard is lower than that the standard of “probable cause” which is the standard that is required for an arrest or search of a vehicle, person or home. Reasonable suspicion for investigatory traffic stops of a vehicle requires that the police have “articulable facts that criminal activity is afoot.” Evidence that criminality is afoot can be a motorist weaving, speeding, driving without his or her seatbelts off, an equipment violation such as driving with one’s license plate lamp out, etc.. These are facts that if observed by an officer allows the officer to legally pull over a driver to issue a citation.

If an officer states in his report that the reason he pulled a vehicle over late one night was due to that vehicle weaving over the dividing lines that separates the lanes on the freeway then that is a valid reason for stopping that driver. The officer can then approach the driver and request the driver to produce a valid driver’s license, insurance and vehicle registration. If the driver does not have either of the three forms of identification requested then the officer has probable cause to arrest OR cite the driver for the above violations of driving without a valid driver’s license, insurance of vehicle registration. If the officer upon approaching the stopped vehicle smells the odor of alcohol emitting from within the vehicle or the driver, then the officer can legally perform a full blown DUI investigation which includes requiring the driver to exit his or her vehicle, answering pre-field sobriety test questions, submitting to field sobriety tests, and submitting to a chemical blood or breath test. A good DUI defense lawyer will always challenge the reasonable suspicion for the stop of his clients vehicle through an in court legal motion to suppress evidence which challenges the police officer’s reasonable suspicion to stop the vehicle and or challenges the officer’s probable cause to arrest the client. 

The Fruit of the Poisonous Tree Doctrine

The law states that if the reason for a traffic stop or arrest is found to be unlawful/illegal, then anything thereafter the unlawfulness which is discovered by law enforcement is to be suppressed or not usable against the accused in court. This is the Fruit of the Poisonous Tree Doctrine which was first mentioned in the 1963 United States Supreme Court case of Wong Sun v. United States. There the Supreme Court ruled that a defendants statements and the subsequently recovered contraband should both be excluded or thrown out of court and thus not usable against the defendants as fruit of the poisonous tree because the search was done without a warrant. So, if a Judge after hearing evidence from both the defense and the prosecution on a contested motion to suppress evidence, rules in favor of the defense, then anything after the stop of the vehicle will get thrown out of court. That includes Field Sobriety Test evidence, post arrest statements, and more importantly the chemical blood test or breath results.

Real Life Case #1 - No Reasonable Suspicion to Stop a Vehicle - People v. V.S. Case 5LT00272

Attorney P J Voll was retained to represent Mr. V.S. in a first time DUI filed out of the Long Beach Court. The reason for the stop of the vehicle as stated in the police report was that the vehicle driven by V. S. had been weaving and that the vehicle was observed to have weaved into the dividing lanes on the Long Beach freeway. After Mr. Voll obtained the police vehicles dash camera footage, it was clear the Mr. V.S. was not weaving on the freeway at all. Mr. Voll filed a motion to suppress evidence and the Judge who presided over the motion ruled in favor after viewing the video despite the officer testifying in open court that Mr. V.S. was weaving all over the freeway and a danger to other drivers on the highway. As such, the .10/.10 breath test results were suppressed and thrown out of court and the case against Mr. V.S. was dismissed.

Real Life Case #2 - No Reasonable Suspicion to Stop a Vehicle - People v. J.T. Case 7SV02329

This was an interesting win by Attorney P J Voll on behalf of his client who was a 2nd time DUI offender who happened to also be undocumented. His wife and infant son live with him here in Los Angeles and a conviction for a 2nd time DUI would have sent him back to his native Mexico forever. Everything was riding on this case for Mr. J.T. Attorney P J Voll filed a motion to suppress evidence based on no reasonable suspicion to stop the vehicle Mr. J.T. was driving. The prosecutor subpoenaed the wrong witness police officer who never saw the defendant speeding and thus the Judge granted the motion to suppress the breath test results and the case was dismissed. This case being thrown out really saved the life of Mr. J.T. and he vowed to never ever drink alcohol again.