8 DUI Checkpoint Mistakes Police Make That Can Be Challenged In Court

In this post, I am going to show you exactly which mistakes police officers can make when instituting a DUI checkpoint.

In fact:

I have used these mistakes to file motions to suppress incriminating evidence or to file motions to dismiss charges.

Let’s get started…

Are DUI Checkpoints Legal in California?

Yes, under state law, police departments are permitted to set up roadblocks where police officers may detain motorists for a short time to determine if they are driving while impaired1.

Note: Police officers do not need probable cause to stop you at a checkpoint.

Are There Checkpoint Guidelines That Must Be Followed?

There are numerous guidelines that police departments are required to follow or a defendant arrested at a checkpoint may successfully challenge his or her arrest.

policies folder
Examples Of Guidelines Include:
  • There must be a neutral, pre-determined process by which vehicles are selected to be stopped;
  • The checkpoint must be adequately identified;
  • There must be advance notice to the public of the roadblock; and
  • All detentions must be as short as possible.

Let’s take a look at the details of the police requirements and then how we can challenge any police failures to follow proper protocol.

8 Factors Used In Determining The Legality Of A DUI Checkpoint

1. A Supervising Officer Must Make All Constitutional Decisions

Before the checkpoint is established, an administrative officer and not a field officer or one on the scene must make operational decisions about how the checkpoint is to be conducted.

Why Is This Done?

This is to prevent unconstitutional profiling that would single out persons on the basis of race or national origin or other particular traits for detaining and questioning and to reduce the potential for arbitrary and capricious enforcement2.

Such decisions include…

  • The date for the checkpoint,
  • Location of the site, and
  • How they are to select vehicles to be briefly detained.

2. Motorists Must Be Stopped On An Impartial Basis

A decision as to which vehicles are to be stopped is to be made by the administrative officer before the checkpoint is established on-site.

For example, the officers may be directed to stop 5 consecutive vehicles, let 2 proceed, and then stop the next 5 cars.

It may not be at the discretion of any field officer. 

3. The Location Must Be Reasonable

The checkpoint must be in an area where there have been a high incidence of DUI arrests or alcohol-related accidents so that the checkpoint can be more effective in stopping impaired drivers. 

map of los angeles

4. There Must Be Safety Precautions

Another requirement is to implement safety precautions so that motorists can safely stop and navigate to and through the checkpoint in an area that can safely accommodate the checkpoint and the flow of traffic.

For example, there should be adequate lighting and the checkpoint set up at a time and place where the volume of cars passing through is manageable.

5. The Time And Duration Must Be Reasonable

There is no time limit on how long a checkpoint can be operational. It is permissible for one to last an entire weekend so long as the burden on motorists is not substantial. 

Those supervisors or administrators tasked with setting up the checkpoint should ensure that the time of day when the checkpoint will be in operation and its duration are reasonable so as to cause only minimal inconvenience to motorists.

For instance, a checkpoint on a busy stretch of roadway during rush hour is probably unreasonable.

6. There Must Be Signage For The Checkpoint

Motorists must be alerted to the presence of the checkpoint by signs posted in advance of the checkpoint.

Officers can also have flashing lights on several vehicles along with a number of marked police cars leading to the stopping point.

flashing police lights

This gives drivers time to see that they are approaching an official area where they may be asked to stop and minimizes a feeling of fear that could lead to motorists suddenly and unsafely attempting to avoid the checkpoint. 

Is It Illegal To Turn Around At A DUI Checkpoint?

No, you may legally turn around to avoid a checkpoint so long as you do so safely and without violating any traffic laws.

turn signal on

For example, if you make an illegal or unsafe U-turn, you will likely be stopped and cited.

If you do turn around at a checkpoint and do so safely and legally but are stopped nonetheless, your defense attorney can assert that the officer had no probable cause to stop and detain you.

7. Drivers Should Be Detained For The Shortest Time Possible

An essential component of a DUI Checkpoint is to detain drivers for the shortest time possible so as to lessen the intrusive nature of the operation3.

Officers are trained to quickly recognize signs of impairment that can include:

  • Slurred speech
  • Odor of alcohol
  • Dazed appearance
  • Glassy or bloodshot eyes
  • Incoherent responses or speech

Generally, an officer will ask a few questions of the motorist and observe his/her appearance and demeanor within a minute or so of the stop.

If no signs of impairment or intoxication are immediately noted, the motorist should be allowed to leave.

If these or other signs of possible impairment are observed, then the officer may further detain the motorist so long as the officer reasonably suspects impairment. 

If signs of impairment are observed than the officer may ask for the following:

Do You Have To Stop At A DUI Checkpoint In California?

Yes, you do have to stop since brief detention at these checkpoints is not considered a “seizure” under the U.S. Constitution but an administrative inspection.

Can A Driver Refuse To Cooperate?

You may politely refuse to answer any questions by police such as whether you have been drinking, whether you were at a bar or restaurant, or any other question.

You can also refuse to undergo any field or roadside sobriety tests that you are asked to perform.

Watch this video to see how and why you should refuse field sobriety tests.

Am I Required To Take A Chemical Test At A Checkpoint?

Under California’s implied consent law, you are legally obligated to undergo a chemical test of your breath or blood so long as the officer had probable cause to arrest you and to make the request and give you the required admonitions about the test.

If you refuse chemical testing and probable cause is found, you face significant civil penalties such as loss of your driver’s license for at least one year and certain criminal consequences.

What Happens If You Do Not Have A License At The Checkpoint?

If you merely forgot your license and it is valid, you can give the officer your license number if you can recall it and after checking it, the officer may allow you to proceed provided you show no signs of impairment.

However, you can be ticketed for an infraction for not having your license with you but you will be required to produce it to a court clerk or in traffic court and have the matter dismissed.

If you do not have a valid driver’s license, you can be arrested pursuant to California vehicle code 12500 vc and face a fine of up to $1,000.

Can Your Car Be Impounded If You Do Not Have A License At A Checkpoint?

Yes, but only if you were driving on a suspended license.

impound paperwork

However, you can contact a validly licensed individual to retrieve the vehicle from the checkpoint to avoid impoundment.

calling a friend

If it is impounded, it can be kept for 30-days and costs can exceed $1,500. If the fee is not paid, it is subject to being sold at auction.

Note: California Assembly Bill 353, which is currently California Vehicle Code 2814.2 does not allow officers to impound your car if your only offense at the DUI checkpoint was not having a valid license.

8. The Checkpoint Must Be Advertised In Advance

Any DUI checkpoint must be advertised to the public in advance. Notice is generally reasonable if given one week in advance4.

The purpose of the notice is to deter drivers from drinking and driving in these areas, which are generally locations where high incidences of DUI arrests or alcohol-related accidents have occurred, and to put motorists on notice that their liberty or privacy could be violated if only for a minimal time. 

Where is the Checkpoint Notice Found?

Notice of the checkpoint including the date and time can be found on law enforcement websites, television and radio news stations, and in your local newspaper or town website. 

Challenges To A DUI Checkpoint

The first step in potentially challenging a DUI checkpoint stop is obtaining the police packet that law enforcement agencies are required to maintain when they implement a DUI checkpoint.

The packet is acquired from the prosecutor as part of the discovery process and inside that packet is the detailed information on the steps taken by law enforcement before and during the checkpoint.

Important Note:

Not all of the 8 guidelines are considered equal; indeed, some are more equal than others.

For example, there is no standard for where to post warning signs about the approaching checkpoint or that a certain number of marked police vehicles be present with lights flashing.

So long as it appears reasonable, then a court will likely not invalidate your arrest on this basis alone.

What Are Some Of The Credible Challenges That Can Be Made To A DUI Checkpoint?

A credible challenge may be mounted if there is evidence that you were stopped at random and not pursuant to a pre-arranged or neutral method outlined by a supervisor regarding which vehicles will be stopped.

If the method becomes too burdensome, there must also be in place an alternate routine.

Should your DUI defense attorney demonstrate that officers in the field decided on their own to use their own method of stopping cars that did not comply with the pre-determined one, then you may have a successful challenge. 

Other Issues That Can Be Raised In A DUI Checkpoint

  • What were the identities of the persons arrested for DUI? Were all or substantially all defendants of a certain race, ethnicity, age or appearance?
  • How long was each driver detained?
  • How much advance notice was given to the public about the checkpoint?
  • Were motorists allowed to safely avoid the checkpoint or were they detained or blocked from doing so even if they were doing so safely and legally?
  • Did the checkpoint have sufficient signs of its official nature?
  • Did the officer have a reasonable suspicion to detain the defendant?
  • Was there probable cause to request the defendant to perform field sobriety tests and to take a chemical test of his or her blood or breath? (Generally, there is a vehicle or van where the breath test can be administered)
  • How were the checkpoint procedures established—this may entail a review of all documents and communications regarding its operation
  • Where was the checkpoint established and was it in a reasonable location?

Challenging a DUI Checkpoint stop can be complex and requires that your defense attorney have the knowledge and experience in mounting a successful defense based on the lack of adequate safeguards in how the operation was set up and the methods used to detain and arrest those suspected of DUI.

Important DUI Information

Next Steps If You Need Help

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

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

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

Request A Free Consultation 818-351-9555 


  1. Ingersoll v. Palmer (1987) 43 Cal.3d 1321; See Also People v. Hyde (1974) 12 Cal. 3d 158, 165-166 []
  2. Ingersoll v. Palmer, supra, 43 Cal.3d 1342 []
  3. Michigan Dept. of State Police v. Sitz, 496 U.S. 444 (1990). []
  4. People v. Banks, 6 Cal.4th 926 (1993). []

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