13 Examples Of Lack of Probable Cause For A DUI Traffic Stop or Arrest

Lack Of Probable Cause

In order for a law enforcement officer to stop your vehicle, they must articulate specific details that rise to the level of reasonable suspicion that a crime has been commited.  Reasonable suspicion only requires a minimal level of justification for the stop such as a traffic violation, equipment violation, or erratic driving. Generalized suspicion is not enough1.

While reasonable suspicion is required for a dui traffic stop, a lack of probable cause can prevent you from being arrested.

We have put together 13 examples of a lack of reasonable suspicion for a DUI stop or lack of probable cause for a DUI arrest so that you can understand when an officer may have violated the law.

1) Police Not On The Scene

Police come to your residence investigating a car accident based only on your license plate having been identified by a third party as being involved in the collision. The witness could not provide any description of the driver.  Upon arrival to your home several hours later, the police officer finds you at home and under the influence of alcohol and arrests you for DUI.  

In this case, the officer observed you at your home as stumbling, slurring your speech, or exhibiting other indicia of being under the influence. If you make no statements or admissions to the officer, there is no probable cause to arrest you for DUI.  The officer needs to do a further, more in-depth investigation into who the driver could have been. 

2) Not Clear Who Was Driving

You are found standing outside of your vehicle with other persons, all similar height to you around the car and no one admits to driving. 

Even though the car is registered to you, there is no way for the officer to know who was driving and if that person was under the influence at that time. 

3) Racial Profiling

You were stopped based on your race such as for driving in a predominantly Caucasian  neighborhood.

Race, religion, national origin, gender identification, or creed cannot be the basis for stopping you. Although police will rarely, if ever, state that this is the sole reason why you were pulled over, your criminal defense attorney will have to demonstrate a substantial disparity in the race of persons who are stopped and detained or a disproportionate ratio of police stopping persons of color.

Communications within the police department or from dispatchers, if recoverable, can point to racial bias in targeting certain groups of people, 

4) Vehicle Never Moved

You are arrested for DUI because the car engine was on but the officer never saw the vehicle move2.

Under California law, the officer must have seen your vehicle move, even if it was a few inches, or that you were about to engage the vehicle by turning it on. However, if the vehicle rolls forward or backward because the emergency brake is off and despite the engine being shut off, this constitutes driving.

Furthermore, the officer can use circumstantial evidence of your driving to make the arrest. This includes finding you asleep inside your vehicle, while in the middle of an intersection at a red light.  While the vehicle hasn’t moved, the officer can reasonably conclude that you must have driven it to that destination, while under the influence. 

5) Stopped Out Of Turn

At a DUI checkpoint, where the plan was to stop every other vehicle, the officer stops your vehicle out of turn and for no articulable reason. The stop may be challenged as unlawful. 

DUI checkpoints are legal in California so long as the stops are minimally intrusive and police follow certain criteria such as:

  • Supervising officers oversee the process and make all decisions on its operation
  • Basis for stops are neutral (random)–cannot stop you because of race or condition of your car
  • Checkpoint is reasonably and safely located
  • Roadblock was publicly advertised in advance
  • Roadblock was clearly marked as such
  • There was a way for motorists to turn and avoid the roadblock
  • Detentions are lasting too long

If the officer did not follow the plan of the checkpoint, and can not point to any articulable reasons for the stop, the stop itself may be challenged and all information obtained excluded from the evidence of the case if the motion brought by the defense attorney is granted. 

6) Merely Leaving A Bar

You were stopped because police saw you exit a bar after having observed the bar for several hours and see get into your vehicle and begin to drive. 

Merely because you left a bar after having been there for several hours does not justify a stop absent the officer having observed you violate a specific traffic law such as speeding, making an unsafe lane change, or failing to stop at a red traffic signal, or that you were weaving within or outside your lane of traffic or other unsafe driving conduct. 

7) Court Motions

At a Penal Code §1538.5 motion to suppress or Penal Code § 995 hearing if a felony, the officer provided no specifics on your driving conduct, performance on sobriety tests, or your demeanor and only testified generally that he stopped and arrested you based on these factors. 

The officer must articulate specific facts that lead to the conclusion that a crime was committed. If the officer can only remember generalities or refuses to divulge the specific reasons for the stop or arrest, the evidence may be suppressed. 

8) Late Night Driving

You were stopped because you were driving late at night or in the early morning hours.

If the officer is merely fishing because he/she believes that a person driving just after bars close is likely under the influence, but has no traffic violation or specifics as to the driving that would lend to the conclusion that the driver may be impaired, the stop may be unlawful and successfully challenged in an appropriate motion. 

9) Odor Of Alcohol

The officer arrests you for DUI based solely on his detecting an odor of alcohol and observing your bloodshot eyes. 

These factors alone are insufficient to arrest you for DUI because these facts alone are not reasonably trustworthy information sufficient to warrant a prudent person to believe you had committed a crime3. Also, drinking and driving is not illegal in California or in any other state so long as you are not driving impaired or your blood alcohol level is below 0.08%. 

10) Connected By Name Only

Officers are notified that a person named Steve was seen driving erratically and police know you as Steve and that you have a prior record of DUI and drug activity and stop you when you are seen simply driving.

11) Tinted Windows

An officer stops you based on the erroneous and unreasonable legal assumption that your tinted window is a violation of law4.

However, the officer’s mistake of law must have been unreasonable because the law was clear and unambiguous in stating that tinted windows are legal. If the officer’s mistake was a reasonable one, though, then the stop was likely valid5. It is unclear as to what is a reasonable mistake of law by a police officer.

12) Refuse Chemical Test

An officer arrests you on suspicion of DUI because you refused to answer questions about drinking and/or refused to perform any field sobriety tests. 

Unless the officer can point to other reasons for the arrest, there is insufficient probable cause.

13) Swerving Once

An officer concludes you are driving under the influence because you swerved once but otherwise remained wholly within your lane for an appreciable amount of time.

The common features of these last 4 examples are that the officer failed to either 1) point to a reasonable basis to suspect you had broken the law or were breaking the law in order to justify stopping your car or, 2) lacked a reasonable belief based on specific and articulable facts existing at the time of the event to believe that you were driving under the influence of alcohol or drugs. 

Brief Investigative Stop

The law does allow a brief investigative traffic stop so long as the officer has a

particularized and objective basis for suspecting the person stopped of criminal activity6.

If the officer wishes to detain you for longer than necessary for a routine traffic stop because he/she suspects you are under the influence, the officer must have probable cause. This is a reasonable belief that you are impaired based on the office being able to articulate specific facts supporting a belief that you were driving under the influence of alcohol or drugs. This is a higher standard than reasonable suspicion. 

Probable cause also means that the officer must have a reasonable basis or belief for his suspicion which would cause a cautious person acting in good faith to believe that you are guilty of DUI. The officer must be able to point to known facts existing at the time of the determination that “would lead a man of ordinary care and prudence to believe and conscientiously entertain an honest and strong suspicion that the person is guilty of a crime.”7.

Next Steps

If you have been arrested and would like to learn more about what attorneys charge.

If you want to understand why its important to have an attorney represent you.

If you are ready to discuss a pending case with an attorney contact the Aizman Law Firm at 818-351-9555 for a free confidential consultation.

Get Legal Help Now

Request A Free Consultation 818-351-9555 


  1. People v. Bower (1979) 24 Cal.3d 638, 644 []
  2. Mercer v. DMV (1991) 53 Cal.3d 753, endnote 4 []
  3. Beck v. Ohio (1964) 379 U.S. 80, 91 []
  4. People v. Butler (1988) 202 Cal.App.3d 602, 606-607 []
  5. Heien v. North Carolina (2014) 135 S.Ct. 530 []
  6. U.S. v. Cortez (1981) 449 U.S. 411, 417, 418; Terry v. Ohio (1968) 392 U.S. 1, 21 []
  7. People v. Price (1991) 1 Cal.4th 324, 410; Schmerber v. California (1966) 384 U.S. 757 []

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