Best Defenses for Naperville DUI Arrests: Challenging Probable Cause

Most Naperville drunk driving arrests begin with a stop of a vehicle, usually for an innocuous reason.  Sometimes the reason is so innocuous that your lawyer can persuade the court to "quash" the arrest because there was no probable cause. 

Probable Cause

Before anyone can be arrested in Naperville and charged with a Naperville DUI ordinance offense, the arresting officer must have had probable cause to stop the vehicle the individual was driving in.  Moreover the officer must have reasonable grounds to require the individual to perform field sobriety test and administer a chemical test to the individual.  The United States Constitution's Fourth Amendment, which is applicable to the states through the Fourteenth Amendment, protects individuals from unreasonable searches and seizures. Therefore, the police must have probable cause to stop and question the driver of a car for suspicion of drunk driving before such questioning, and searches incident thereto, will be upheld. As with many of the other pre-trial motions, a motion based on lack of probable cause can either be brought as a motion to quash arrest, (when the evidence obtained, if precluded from production into evidence, will warrant a dismissal of the charges), or, in the alternative as a motion to suppress, (when the evidence obtained, if precluded at trial, will merely prohibit the Prosecution from presenting part of its case). The analysis of the cases presented in this section applies either to motions to suppress or to dismiss.

While an arrest requires probable cause, an investigatory "stop" merely requires a reasonable suspicion by the investigating officer. See, for example, People v. Legions, 382 Ill.App. 3d 1129, 890 N.E.2d 700 (4th Dist. 2008).  What is reasonable always will depend on the facts and circumstances of the particular case.  People v. Queen, 369 Ill.App.3d 211, 859 N.E.2d 1077 (2nd Dist. 2006).  In DUI cases, Illinois courts have uniformly held that probable cause exists when the facts and circumstances known to the arresting officer are sufficient to warrant a person of reasonable caution to believe that an offense was committed.  People v. Bulmann, 212 Ill.App.3d 795, 571 N.E.2d 850 (1st Dist. 1991). 

In terms of a dui traffic stop, probable cause can be based for example on speeding.  However, the means that the officer used to determine his or her conclusion of excessive speed can and should always be employed in a motion challenging the stop on that basis. The same is true with the common charge of "improper lane usage." Not all movement outside the lane jusifies the stop of a vehicle.  For example, the Illinois Appellate Court has held that a trial court can properly conclude that a Defendant's non-hazardous, momentary crossing of the center line is not reasonable grounds for a traffic stop.  People v. Decker, 181 Ill.App.3d 427, 537 N.E.2d 386 (3d Dist. 1989).

So if you've been charged with a Naperville DUI, your legal defense with the Law Offices of Brent M. Christensen will always begin by looking closely at the issue of probable cause - not only for the DUI arrest but also for the traffic stop that led to the arrest.