Criminal Defense in Ventura County
Determining Probable Cause in DUI Cases

Determining Probable Cause in DUI Cases

Before the police can ever make an arrest for suspicion of driving under the influence (DUI), they need to have fair and justified reasons for doing so. Most DUI cases do not start with someone testing over the legal blood alcohol concentration (BAC) limit – 0.08% for adults with standard licenses, 0.04% for adults with commercial licenses, and usually 0.00% to 0.01% for minors. Instead, highway patrol officers need to establish through a “probable cause” basis that an arrest is necessary and legal.

What is probable cause, though? To put it simply, the police must see enough circumstantial evidence to be able to reasonably assume a driver is intoxicated. If this sounds strangely vague or informal for police work, that is because it is. Probable cause effectively allows an officer’s own discretion to decide whether or not to arrest someone.

Common examples of behaviors or actions that build up to probable cause include:

  • Dangerous driving: Any sort of driving pattern that could be described as erratic or reckless – speeding, tailgating, swerving, etc. – can become probable cause for pulling a driver over and making a DUI arrest.
  • Slurred speech: A commonplace consequence of intoxication is slurred speech. If a police officer notices a suspect is having trouble speaking clearly, it will likely trigger a DUI arrest through probable cause.
  • Open containers: “In plain sight” rules allow law enforcement agents to use or gather evidence from suspects without a warrant so long as that evidence was easily noticed by the officer, who was also not looking for it originally. A driver who leaves a beer bottle or open container on the passenger seat could be subject to a DUI arrest permitted by both probable cause and in plain sight laws.
  • Smell of alcohol: Evidence can be considered to be “in plain sight” if it is an invisible odor. If a driver rolls down the window to speak to the police and the officer immediately detects the telltale smell of alcohol, it could lead to an arrest.
  • Breathalyzer test: If you agree to take a roadside breathalyzer test, the BAC readout it provides can be used against you to make a probable cause arrest. It is only “probable” because field sobriety tests, including pocket breathalyzers, only make suggestions about your sobriety, but do not provide hard evidence.

Retaining Legal Defense After a DUI

Were you arrested for a DUI after the police officer cited probable cause? You can start building a defense to dismantle the prosecution’s strategies by working with The Law Offices of Jarrod M. Wilfert and our Ventura DUI attorneys. Our team, which is led by former police officers, have handled hundreds of cases successfully throughout the years. Call 805.994.0560 for a free case evaluation.

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