DUI Evidence

If there is one thing that all criminal cases have in common, it is that guilt or innocence is often decided by a single factor - supporting evidence. Fortunately, for those accused of DUI offenses, their situations are no exception. If the prosecution wants to win a conviction in their case, there has to be a clear, undeniable and overwhelming evidence available to support their claim. In essence, proof beyond a reasonable doubt.

While the application of driving under the influence can vary somewhat depending on location, the type of evidence that is collected to prove it is usually the same. It is also true that many cases have been dismissed (or sentences reduced) because of the lack of evidence or the quality of the investigation results.

Although the facts may seem cut and dry in many DUI cases, understanding what makes for good evidence is often harder to figure out. It takes the skill of a seasoned DUI attorney to recognize what types of evidence may hold up in court, which evidence can be thrown out, and evidence that is questionable.

If you feel that the evidence in your DUI case is weak or false, contact the California DUI Law Office of Joshua Kaizuka today to discuss the details of your case. We offer free consultations to everyone that calls and we will quickly answer any DUI questions that you may have.

You can reach us by phone at 916-706-0678.


The majority of DUI cases are comprised of five major types of evidence: Driving Behaviors, Symptoms of Intoxication, Field Investigations, Incriminating Statements and Chemical Test Results.

Although each kind of evidence has elements which can be used to build a case against a suspected DUI offender, skilled DUI lawyers can quickly recognize how and when such information can be contested.


Though most people think of weaving, speeding, and other unusual behavior when it comes to drunk driving, there is often more to the story. Other points to consider include:

  • Was there another reason for the behavior (medications, fatigue, etc.)?
  • Where was the vehicle located (on or off the road)?
  • What was the driver doing (sitting in the front seat or something else)?
  • Were the keys still in the ignition
  • Could the vehicle be driven (or were there mechanical issues)?

These are all questions an experienced DUI attorney should ask when evaluating a case.


Physical appearance and behavior are often used to justify DUI arrests. While it is true that some of these symptoms can be found in intoxicated drivers, many times they are the result of other factors.

  • Bloodshot eyes
  • Slurred speech
  • A flush or red face
  • Trouble standing or walking
  • The smell of alcohol
  • Difficultly comprehending or following directions

Officers are so frequently trained to look for this type of evidence that it is often listed by default on arrest reports whether or not it was found.

Experienced DUI lawyers - like those at the Law Office of Joshua Kaizuka - are quick to point out that many of these same symptoms can be experienced from other things besides just drinking. Common colds, allergies, over-the-counter medications and even non-alcoholic beer can produce similar effects.


This class of evidence is what most people think of when they see DUI arrests on television or in the movies. Drivers are often asked to do things like touch their nose, walk in a straight line or say the alphabet backward.

However, the most common test for field DUI evidence has to do with the use of a Breathalyzer. These devices are utilized to give a basic indication of a suspected driver’s blood-alcohol level. Although meant to be an initial indicator only, breathalyzers are frequently considered the determining factor in deciding if a person is drunk or not.

Even experts will admit these types of portable devices give only a rough estimate of intoxication (at best) in most cases. Blood tests are considered to be a much more accurate indicator of true blood-alcohol levels at the time it is collected.


Most suspected drivers are unaware they are NOT REQUIRED TO ANSWER ANY QUESTIONS at the time of a DUI arrest. Until you are given your Miranda Rights, anything you say can be used against you as incriminating evidence.

Keep in mind that you have the right to ask for an attorney anytime if you feel that your rights may be in jeopardy. And especially in DUI cases, you should seek the help of an experienced DUI attorney who specializes in this type of litigation.

The Joshua Kaizuka has been helping accused DUI drivers for over 15 years. We know how to recognize errors in police procedures and can quickly point out evidence that may not be admissible in court. Contact us today if you need help with your DUI case.


The last type of evidence has to do with the actual testing of intoxication levels. Breath and blood samples can be used to determine this number, but both testing methods can produce errors and often provide inaccurate results.

Breathalyzers are programmed to give readings for an “average” adult, but based on the many physical and chemical differences amongst human beings this type of standard is almost impossible to define.

On the other hand, while blood draws have been scientifically proven to be more accurate, there is significant room for human error when it comes to the testing and storage of these kinds of samples.


Although there are many lawyers out there who will accept DUI cases, there are very few that have the required experience and skills necessary to truly make a difference for their clients. Joshua Kaizuka has defended countless DUI victims in Northern California and can easily spot DUI evidence that will not hold up in court.

If your or someone you know is facing a DUI charge, contact our offices today at 916-706-0678 to learn more about how we can help. The consultation is free, and we are always available to answer any questions that you may have. We know what it takes to win in DUI cases like yours.