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

In this list, I will show you 13 examples of police officers lacking reasonable suspicion for a DUI stop or probable cause to arrest for DUI in California.

In fact:

Lacking reasonable suspicion for a DUI stop or probable cause to arrest are among the most powerful defenses we have used to get DUI cases reduced or dismissed.

Let’s get started…

Lack Of Probable Cause

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. 

police talking to witness

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 DUI 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 move1.

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.

man starting car

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. 

man asleep at wheel

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 you get into your vehicle and begin to drive. 

Merely keaving 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
  • Failing to stop at a red traffic signal, or
  • That you were weaving within or outside your lane of traffic or other unsafe driving conduct2. 

7) Lack Of Specific Details

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.

However, the odor of alcohol is enough to further investigate the possibility that the defendant is under the influence of alcohol.

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 To Answer Police Questions

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.  Provide 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 DUI of drugs. 

Are Police Allowed To Make Brief Investigatitve Stops?

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.

However, 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.

Important Information

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. Mercer v. DMV (1991) 53 Cal.3d 753, endnote 4 []
  2. People v. Bower (1979) 24 Cal.3d 638, 644 []
  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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