One of the general principles of criminal law is that police officers cannot – in most cases – stop people at random just in case they might be committing a crime. With the exception of properly set up DUI checkpoints, this principle also covers DUI stops.
To make a stop, a police officer must have probable cause to think you are committing some type of crime or traffic violation. Without meeting this requirement, even if it turns out you were definitely committing a DUI, the prosecution risks having the entire case thrown out.
What is probable cause?
Generally, probable cause means the officer reasonably believes, based on circumstances, that a crime was or is being committed. Guessing would not suffice – the officer must be able to logically point to the facts that supported his or her decision to make the stop.
How does this apply to DUI cases?
In the case of a DUI, probable cause typically consists of indicators that you are operating the vehicle in an impaired condition. Some examples include dangerous driving, breaking traffic rules, ignoring signage, drifting or weaving in and out of traffic. Officers investigating a collision may also have probable cause that would likely support a DUI arrest if an involved driver was, in fact, under the influence.
In some cases, an officer may stop a driver due to the belief that a crime other than a DUI was or is being committed. For example, your car may match the description of that of a robbery suspect. However, courts will generally look to the sum total of the circumstances to determine if the stop was reasonable. In such situations, the existence of probable cause can present a complicated question.
What happens if there was no probable cause?
An illegal stop can invalidate evidence the officers gather as a result of the stop; sometimes, this can even lead to a dismissal of charges. This is just one reason you should never assume the prosecution has such a strong case against you, you might as well agree to a potentially damaging plea bargain.
Instead, contact an experienced attorney as soon as you can. Your lawyer can comprehensively evaluate your case and figure out an effective approach.