Law Offices of Erik Steven Johnson

247 N. Third Street, San Jose, CA 95112

Call Today for a Free Consultation | Se Habla Espanol


Santa Clara County DUI Evidence Defense Lawyer

Cupertino Drunk Driving Defense Lawyer

What Evidence Are Police Looking for in California DUI Stop?

The collection of evidence in most DUI cases begins even before a vehicle stop is made. The reason for the stop, or sometimes the pretext, is a Vehicle Code violation, such as speeding, or an illegal lane change. However, even before the police officer makes contact with the driver, he or she is noting potential evidence for a DUI investigation, including perceived "impaired driving."

The evidence that will be collected and used in a DUI investigation varies but typically involves observational, testimonial and forensic evidence. For more information on evidence in your DUI case, contact our law firm today.


  • Police observations and noted patterns of "bad driving."
  • Police observations regarding the smell of alcohol coming from the driver or from inside the vehicle.
  • Physical observations of the driver, including flushed faced, slurred speech, watery eyes and unsteady gait.
  • Performance of field sobriety tests, including horizontal nystagmus (lack of smooth pursuit of pupil), Romberg test (counting to 30), one-leg stand, and walk and turn.
  • Driver's admission regarding use of alcohol or drugs

Forensic Evidence

  • Preliminary breath results (PAS) and breath-alcohol analysis
  • Chemical tests, including blood, breath or urine and post test analysis and handling
  • Retrograde extrapolation or projecting blood levels back to the time of driving
  • Partition ratio analysis and the absorption of alcohol

Note: Under California law, once you decide to operate a motor vehicle you are deemed to also give consent to a chemical test (blood, breath or urine) without the requirement of a warrant. Refusing to submit to a chemical test will result in a one-year license suspension with no restricted privileges.

Contact Our San Jose Law Firm For Answers To Your Questions

Your lawyer must act quickly to collect this evidence, analyze the weaknesses and prepare a defense to a charge of driving under the influence. You only have ten (10) days from the time of your arrest to demand a hearing with the Department of Motor Vehicles to preserve your driving privileges. Contact your San Jose criminal defense lawyer at the Law Office of Erik Steven Johnson to find out what needs to be done in your case at 408-246-3004.

Back to Top