the dui anatomy of a flowchart

DUI Arrest Process in Napa County 

A simple driving error at an inopportune moment can quickly lead to a traffic stop. In most scenarios, a regular traffic stop results in a traffic ticket or a warning. However, if the driver has consumed any alcohol or marijuana, what began as a routine traffic stop can escalate to criminal DUI charges. Alarmingly, drivers may face DUI charges even if they are not over the legal limit. This underscores the importance of contacting experienced DUI attorneys at Wilber Law Offices, P.C., who will thoroughly investigate your case and fight against a criminal conviction.

DUI Defenses and Law Enforcement Violations

Law enforcement officers are required to adhere to certain rules and regulations to ensure they do not infringe upon the Constitutional rights of drivers in California. However, police officers do not always abide by these rules and may jeopardize your rights. Any violations by law enforcement during the DUI arrest process, from the traffic stop to chemical testing, can form the basis for contesting DUI charges.

Traffic Stops for Impaired Drivers in California

The police must have a reason, or "reasonable suspicion," to conduct a traffic stop. They do not need to suspect that a driver is under the influence to stop them, as long as the stop is justified by a suspicion that the driver has broken a traffic law. It usually does not take much to warrant an initial traffic stop. Common violations that can trigger a stop include:

  • Speeding
  • Failing to signal a lane change
  • Rolling through a stop sign
  • Broken tail light
  • Driving without headlights at night
  • Tinted window violations
  • Littering from a vehicle

DUI Investigations After a Traffic Stop

Once the initial traffic stop is made, the police may begin a DUI investigation based on their interaction with the driver. Even if the stop was for a minor infraction like speeding, specific and articulable facts leading to a reasonable suspicion of drunk driving can justify further investigation. 

Common signs that may alert officers to drug or alcohol use include:

  • Odor of alcohol on the driver’s breath
  • Smell of marijuana in the car
  • Visible open containers in the vehicle
  • Slurred speech
  • Bloodshot eyes
  • Admission of drinking alcohol
  • Inconsistent statements about the driver’s destination

DUI Checkpoints in Sonoma County

DUI checkpoints, also known as sobriety checkpoints or roadblocks, are exceptions to the reasonable suspicion requirement for traffic stops. Although challenged in California courts, these checkpoints have been upheld as lawful, provided they meet certain criteria to be considered constitutional. If DUI checkpoints do not follow these criteria, an experienced Sonoma County DUI attorney may challenge their legality. 

Required criteria typically include:

  • Public advance notice
  • Reasonable location
  • Neutral criteria for stopping vehicles
  • Minimal detention time for drivers

Field Sobriety Tests in Santa Rosa

As part of a DUI investigation, police officers may request drivers to perform field sobriety tests (FSTs) to determine impairment. It is crucial to know that in California, field sobriety tests are not mandatory, and there are no penalties for refusing to perform them. 

Standard FSTs, which are reportedly more accurate, include:

  • One Leg Stand Test
  • Walk and Turn Test
  • Horizontal Gaze Nystagmus (HGN)

Even if an officer seems to suggest these tests are mandatory, drivers should remember that refusal carries no penalty. Drivers can and have been arrested for DUI after "failing" an FST while sober due to factors such as medical issues, environmental conditions, improper instructions, nervousness, or police procedural errors.

Blood-Alcohol Level and DUIs

In California, a DUI can be charged if a driver's blood alcohol content (BAC) exceeds the legal limit. Known as a per se DUI, this charge stands regardless of whether the driver was operating the vehicle safely. A BAC over 0.08% for most drivers constitutes illegal driving. However, DUI charges can also be filed if a driver is impaired with a BAC under the limit. Factors affecting how substances impact different individuals include sex, weight, body composition, food intake, alcohol percentage, serving size, dehydration, use of over-the-counter drugs, and drowsiness.

Chemical Testing After a DUI Arrest

In DUI cases, chemical test results are often primary evidence. Most alcohol-related arrests use a breath test, while drug-related arrests may involve blood or urine tests. These results help prosecutors prove a driver’s intoxication level in court. Under California’s implied consent laws, drivers agree to chemical testing after a DUI arrest. Refusing this test can lead to a one-year license suspension without the possibility of a restricted license. Despite this, lawyers can challenge chemical testing procedures, potentially excluding these results from evidence if proper protocols were not followed.

Contact Our Santa Rosa DUI Defense Lawyers ASAP

Experienced DUI defense lawyers will thoroughly investigate your case to identify the best strategies to combat DUI charges. If law enforcement officers took shortcuts, violated rules, or infringed upon your rights, you should not have to suffer the consequences. Contact the Santa Rosa DUI defense team at Wilber Law Offices as soon as possible to ensure the protection of your rights and explore all possible defenses. 


Reach out to Wilber Law Offices today for a FREE consultation.


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