| Read Time: 3 minutes

California laws targeting drivers who are under the influence of drugs or alcohol impose harsh penalties on those who are caught and convicted. As strict as the state is in enforcing its DUI laws, police and other law enforcement agencies must take care not to infringe upon the rights people enjoy under the U.S. Constitution to move about without interference from government or from those acting on before of the government.

DUI arrests and probable cause

Police cannot stop your car to determine if you have been drinking without having probable cause to do so. Probable cause is when a police officer has reason to believe you committed or are about to commit a crime. This belief must be supported by the facts known to the officer. The U.S. Supreme Court applies a reasonably prudent person standard to determine if an officer’s belief rises to the level of probable cause. In other words, would a reasonably prudent person faced with the same information as the police officer have reason to believe a crime is being committed?

The challenge for a police officer when making a DUI arrest is that practically all of the facts supporting his or her belief about the driver being drunk are not revealed until after the traffic stop has already been made. A hunch or a gut feeling about a motorist does not justify stopping a vehicle even if the driver turns out to be driving under the influence. As the Supreme Court has held in many decisions over the years, the fact the police officer’s hunch was correct does not justify an illegal stop.

Of course, if a police officer observes a motorist disobey a stop sign or commitment some other traffic violation, the officer has the right to stop the vehicle. Observations made at that time about the physical condition of the driver could justify an arrest on a DUI charge.

Reasonable suspicion to stop a vehicle

If an officer does not observe a clear violation of the traffic laws, there might still be an opportunity to stop the vehicle. Reasonable suspicion is a principle recognized by the Supreme Court that allows police to stop a motorist to conduct a brief investigation absent having probable cause.

Recognizing the training police receive and their ability to see things that might not seem suspicious to the average person led the Court to allow police to stop a person for questioning if the officer suspects criminal activity is occurring. Reasonable suspicion in the typical DUI could include the following observations by an officer:

  • Driving erratically
  • Driving much slower than posted speed limit
  • Veering out of the travel lane
  • Constantly braking

An officer observing any of these activities could stop the vehicle and engage the motorist in brief conversation to determine the reason for the behavior.

Building probable cause from reasonable suspicion

An officer may use what he or she observes from interacting with the driver to establish probable cause to believe that the individual is driving under the influence. This might include the following:San Diego dui attorney

  • Watery, bloodshot eyes
  • Slurring while speaking
  • Disoriented
  • Inability to respond to questions
  • Strong odor of alcohol
  • Open containers of alcoholic drinks

The use of field sobriety tests allows the officer to build upon the observations already made of the driver to further submit probable cause for an arrest.

A criminal defense attorney can help

A San Diego criminal defense attorney will review the facts and circumstances of an arrest to determine if probable cause existed for taking a driver into custody. Having experienced and skilled legal representation is essential when charged with DUI. The experienced San Diego DUI attorneys at the Law Firm of Kerry Armstrong can help you, call today for a free consultation!


Author Photo

Kerry L. Armstrong

Attorney Kerry Armstrong opened up his law firm, the Law Offices of Kerry L. Armstrong, APLC, in June 2007. In 2014, 2015, 2016, 2017, 2018, and 2019 Mr. Armstrong was selected for inclusion in the California Super Lawyers list, an honor only awarded to 5% of the nation’s attorneys. In 2017, he was also selected for the Super Lawyers Top 50 in San Diego list. In 2014, he was selected as a Top Attorney by Los Angeles Magazine. Additionally, Mr. Armstrong was also named as a Top Attorney by the San Diego Business Journal in 2014.

Rate this Post

1 Star2 Stars3 Stars4 Stars5 Stars