Possible Defenses for DUI

Possible Defenses for a DUI Explained



No Probable Cause

The prosecution will have to prove there was probable cause to pull over the driver. This can include swerving, disregarding other traffic laws, expired registration, or a burned-out taillight. The exception to the probable cause rule is if the person was stopped as part of a DUI checkpoint because they are not being singled out.



Faulty Testing Equipment or Officer Error

Police use a DUI breath testing machine called the Intoxilyzer 8000. It is designed to measure alcohol in deep lung tissue. However, if the machine is not regularly calibrated, it can give a false reading. If the officer fails to follow strict testing protocols, including eliminating the possibility of “mouth alcohol” being mixed into the machine reading, the test result can be inaccurate. This type of DUI defense leads to reasonable doubt in the test equipment’s accuracy.



Margin of Error of the Test Results

The horizontal gaze nystagmus, the one-leg stand, and the walk and turn are the only three field sobriety tests to show any correlation between performance and alcohol impairment. The National Highway Transportation Safety Administration indicates that the one leg stand suffers from a 35% error rate and the walk and turn from a 32% error rate. Considering this, a DUI attorney could argue that these tests hold too high of a degree of error to be considered reliable in the analysis of probable cause for arrest. Additionally, both the Intoxilyzer 8000 and a blood test have a small margin of error. If the test is just over a .08, the margin of error can create reasonable doubt.

Not on a Public Roadway

If the alleged operation of the vehicle did not happen on a public roadway or a location where the public has access, then there is a defense to a DUI.



Last Gulp Defense

If the person consumes enough alcohol after driving or being in actual physical control of the vehicle to read over a .08, then there is a defense available to the DUI.



No Actual Physical Control of the Vehicle

If the person wasn’t behind the wheel, or the vehicle was not running and the keys were not in the ignition, the prosecutor will not be able to establish the person had actual physical control of the vehicle.