Sara Routhier, Managing Editor and Outreach Director, has professional experience as an educator, SEO specialist, and content marketer. She has over five years of experience in the insurance industry. As a researcher, data nerd, writer, and editor she strives to curate educational, enlightening articles that provide you with the must-know facts and best-kept secrets within the overwhelming world o...

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Written by Sara Routhier
Director of Outreach

Joel Ohman is the CEO of a private equity-backed digital media company. He is a CERTIFIED FINANCIAL PLANNER™, author, angel investor, and serial entrepreneur who loves creating new things, whether books or businesses. He has also previously served as the founder and resident CFP® of a national insurance agency, Real Time Health Quotes. He also has an MBA from the University of South Florid...

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Reviewed by Joel Ohman
Founder, CFP®

UPDATED: Jun 24, 2022

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If you are pulled over by the police while driving your vehicle, it can be stressful and scary.

But the stakes are even higher if the police pull you over for a suspected DUI. It is essential to know what to expect, and the police’s arrest process at DUI traffic stops. 

Most Common Mistakes Police Make During & After A DUI

Police Mistakes During or After DUI
No Reasonable Suspicion For A traffic Stop
Misconduct at Sobriety Checkpoint
Misconduct in Field Sobriety Tests
No Probable Cause For DUI Arrest
Misadministration of Your Breath Test, Blood Test, or Urine Sample
Failure to Prove Driving a Vehicle While Intoxicated
Test Inaccuracies From Ketosis or Keto Diet
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The traffic stop and subsequent investigation follow methodical processes.

This is to protect your constitutional rights and the chain of evidence in the criminal justice system. If the law enforcement officer makes mistakes along the way, how do those common mistakes affect your case?

——> DUI offenders that need car insurance.

Why You Need A DUI Defense Attorney

Many people decide to represent themselves when charged with a DUI. “People mistakenly think that nothing can be done to defend against a DWI charge,” according to Dave Albo, a DUI lawyer. 

An attorney, however, sees a DUI arrest very differently. They see it as an opportunity to help the defendant, carefully reviewing the case’s facts and determining if the arrest was even legal.

What a DUI defense attorney may look for with your DUI case.
Test was given by someone that was not certified to provide the test.
Chain-of-command was broken while handling the test results.
Breathalyzer had not been calibrated according to schedule.
Police report contains conflicting or missing data.
Police failed to prepare the proper paperwork.
Defendant was detained for too long.
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Top & Common Police Errors in DUI Cases

Police officers make errors in a DUI investigation that may aid in dismissing or reducing your charges. It is essential to understand your rights and responsibilities as well as those of the police officers.

1. No Reasonable Suspicion for the Traffic Stop

Reasonable suspicion is required for a police officer to pull you over while driving.

Reasonable suspicion means an objectively justifiable suspicion based on facts that a person is engaged in criminal activity at the time.

——> DUI auto insurance companies.

In traffic stops, this can be driving violations like speeding, failure to signal a turn, or going through a stop sign. It can also be mechanical issues or equipment violations like malfunctioning taillights.

List of acceptable reasons to stop a vehicle by police.
Law enforcement officer personally observing a public offense.
Observing a traffic violation.
Believing that the suspect was involved in a crime.
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If there were no reasonable suspicion for the traffic stop in the first place, the evidence from that traffic stop would be suppressed.

If there is no evidence, your DUI charges cannot be proven.

The National Highway Traffic Safety Administration (NHTSA) has identified several factors used to form reasonable suspicion while driving, such as:

  • Weaving across lines
  • Swerving
  • Unexplained acceleration
  • Slow Speed
  • Failing to signal
  • Stopping unexpectedly

2. DUI Checkpoint Mistakes

The police officers at DUI checkpoints make common mistakes, as well. They need to follow established arrest processes carefully.

Misconduct at Sobriety Checkpoint

During the entire checkpoint encounter with the public, law enforcement officers must act differently. They should not be hostile, threaten you, or call you derogatory names.

They should observe and interview the driver and perhaps ask them to step away from their vehicle.

DUI checkpoint by police during traffic.

Misconduct by police officers at the DUI traffic stop is a possible reason for your DUI charge to get dismissed.

This is the personal contact portion of the sobriety checkpoint, and the officer must communicate with you during this time.

Misconduct at Field Sobriety Tests

A police officer must be trained in field sobriety test methods and follow procedures strictly.

The National Highway Traffic Safety Administration has explicit procedures for tests and training materials you can review to learn more.

The three standardized field sobriety tests are the Horizontal Gaze Nystagmus, Walk and Turn, and One Leg Stand. The latter two tests require divided attention from the driver.

Most common DUI field sobriety tests
Standing on One Leg
Walk and Turn
Finger to Nose
The Rhomberg Balance Test
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The NHTSA determined these are the three acceptable field sobriety tests because they have been scientifically validated through lab studies to prove alcohol impairment markers in each of the three tests.

3. No Probable Cause for DUI Arrest

Probable cause can only exist if objective facts support that the person arrested has committed a crime, in this case, driving while under the influence.

If the arresting officer did not have probable cause, they should not have made the arrest.

Probable cause could come from the results of field sobriety tests, breath tests, an auto accident, or the arresting officer’s visual observations of your behavior.

4. Misadministration of Your Breath Test, Blood Test, or Urine Sample

Breathalyzer tests have to be administered carefully. Police officers must be trained and certified, and the instrument must be calibrated and maintained.

Police giving a DUI suspect a breath test on the side of the road.

Police officers have to administer breath tests to DUI suspects carefully with proper protocol and procedure. A couple of the most common police mistakes that help DUI cases are breathalyzer not calibrated, and the breath test was given by someone not certified.

The police department must keep records of all of this. Any deviations from proper maintenance or administration call into question the administering department’s competence and arresting officer.

If the evidence cannot be used from your breath test or blood test, that may cause subsequent charges to be dismissed.

5. Failure to Prove Driving a Vehicle While Intoxicated

The police officer may not be able to prove you were driving a vehicle while intoxicated. The most likely way this would happen is if the field sobriety and breath tests returned negative results.

The police officer may not provide accurate documentation, field notes or may fail to attend hearings to give their deposition.

——> Understanding Ignition Interlock Devices (IID’s).

This could result in their failure to prove you were driving while intoxicated.

6. Test Inaccuracies From Ketosis or Keto Diet

Many people follow a Keto diet made popular by social media influencers and bodybuilders. A keto diet works by putting your body into ketosis based on what you eat.

Ketosis is a state resulting from a low-carb diet wherein more ketones are in the body. This is good for weight loss but bad for breathalyzer results.

Ketones are similar in composition to isopropyl alcohol, which is read the same as ethyl alcohol by breath tests. This can cause an ‘alcohol mouth’ where the breath smells like alcohol and the breathalyzer results in a false-positive result.

Increase in Car Insurance Rates Could Be the Biggest Expense After A DUI

Depending on the state where you get a DUI charge, your auto insurance rates will increase from 50 to 146%. And you will have increased car insurance rates for at least three years. In California and Georgia, a DUI will remain on your driving record for ten years.

CompanyWithout DUI*With DUI**
State Farm$1,974$2,842
The Hartford$2,043$2,931
National Average$2,287$3,364
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*With a full coverage premium including comprehensive, collision insurance, and uninsured motorists coverage as required by state law.

**Includes SR-22 form in most states. Florida and Virginia it is an FR-44 form.

Frequently Asked Questions

How Can Police Errors Help a DUI Case?

Arresting officers must follow meticulous police procedures during traffic stops, field sobriety tests, and DUI arrests. If they deviate from these established police procedures, it throws into question the results from their tests. Errors by police can cause evidence to be dismissed, and without evidence, your DUI case may not be able to proceed.

What are the Most Common Police Errors for a DUI?

The first major mistake law enforcement can make during the collection of your breath sample is by failing to properly maintain the breathalyzer.

Some of the most common police errors in DUI cases include not following procedures for field sobriety tests or breath tests, failing to document thoroughly or save their field notes of the investigation, and not having reasonable suspicion to pull you over for the traffic stop leading to the DUI charges.

In many cases, a simple clerical error or some faulty equipment is the difference in walking away or facing jail time and thousands of dollars in fines.

Are You Able To Get Your DUI Dismissed When Police Make Mistakes?

You may be able to get your DUI charges dismissed based on the police’s errors throughout the investigation. The police must prove their suspicion you were driving under the influence through scientifically validated methods – if they deviate from these methods, either intentionally or inadvertently, it can invalidate the results. If law enforcement officers make a mistake at one step, it can raise doubt about the entire investigation and cause evidence to be thrown out. Without evidence, the DUI charges may not be supported, and the case could be dismissed.

Should an officer force a defendant to produce a blood sample, usually by restraining the individual against his will, then the officer’s failure to obtain a warrant should render the blood sample result inadmissible at trial.

Where do you Look for Errors in the Police Report?

You should review the entire police report carefully. Read through the officer’s deposition and narratives where they explain the course of events. Your test results should be accurate and have basic details like time, date, and location. Sometimes officers will confuse days of the week or make a mistake with the time of day. Your details should be correct, as well as your vehicle information.

Police reports use codes to describe many things, such as weather, road conditions, precipitating events, and contributing factors. You can search online for police report decoders for your state to use in reviewing your police report.

What Are My Chances of Getting a DUI Case Dismissed?

This depends on your circumstances. It helps to review the evidence, including the police report and deposition from the officers. Talk to your attorney for more information on the details of your specific case.

Even if the police have you dead to rights, a skilled lawyer will know the best ways based on science and law for how to beat a DUI technicality case effectively in court under the new rules in each state.

How to Learn More

To learn more about common police mistakes in DUI cases, contact our experts today at AutoInsureSavings. Our licensed professionals will be happy to answer any questions you have.


– “Legal Resources, Reasonable Suspicion to Stop a Vehicle.”
– National Highway Traffic Safety Administration. “DWI & DUI Detection & Standardized Field Sobriety Testing.” (SFST).
– “How much “probable cause” do the police need?
– “Ten Signs You Are In Ketosis.”

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