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First DUI in San Diego

DUI Traffic Stop – Was there Probable Cause?

After a DUI arrest, it’s easy to assume that the evidence the police have collected is too much to overcome. The arrestee may have failed a field sobriety test, or been found to be over the legal limit in a breath or blood test. Even if this is the case, it’s important to understand that the law provides several safeguards to ensure that the police did not violate the rights of the arrestee when collecting evidence. Any evidence that is collected in violation of these rights should be suppressed, or thrown out, and may leave the prosecution with no choice but to dismiss the case. In most of these cases, the admissibility of evidence often boils down to whether the police had “probable cause”.

The first hurdle the prosecution must overcome, is proving that the initial traffic stop was permissible. In other words, the police must show that they had some reason to pull the driver over.1 At this stage, any traffic violation is sufficient to warrant a stop; even if it does not immediately suggest that the driver is under the influence. For example, a broken tail light, expired registration, or rolling a stop sign all permit the police to stop the vehicle. While there are a number of violations that can lead to a lawful stop, the prosecution still bears the burden of proving that the reason for the stop did in fact exist. If the police report states that the driver was initially stopped for rolling a stop sign, but eye-witness or video evidence proves that a full stop was made, the traffic stop should be found invalid, and the resulting evidence should be suppressed. This prevents the police from pulling over cars without cause, and remains in effect even if the stop ultimately reveals evidence that the driver was over the legal limit.

Furthermore, in DUI cases involving a lawful traffic stop, the prosecution still must prove that probable cause existed for the DUI investigation.2 This means the prosecution must point to specific and articulable facts that reasonably suggest that the driver is under the influence. For example, a broken tail light or expired registration by itself in no way suggests that the driver is drunk. The police must be able to point to additional facts such as slurred speech, the smell of alcohol, or some erratic behavior before a DUI investigation can be initiated. If the prosecution cannot point to these facts, evidence obtained as a result of the investigation should be suppressed.

Finally, in addition to the traffic stop and investigation, the police also need probable cause to make the actual DUI arrest.3 Typically, this will be proven with evidence of a failed sobriety or breath test. However, it’s important to remember that the police must follow the law in all of the steps leading up to the test. Essentially, if a breath test should not have occurred, evidence of the test should not be admissible.

If you, or someone you know, has been involved in a DUI arrest, do not assume that evidence of intoxication is sufficient to lead to a valid arrest or conviction. It’s important to consult an attorney to ensure that your rights are being protected at every stage of the case.

If you are arrested for your first DUI, you may be unfamiliar with the California legal system, especially as it relates to DUI law. A private attorney at San Diego DUI Attorney can walk you through the steps of the DUI process as well as determine the most effective defense strategy to ensure a positive outcome.

According to California Vehicle Code Section 23152, it is illegal to operate a vehicle if any of the following are true.

  1. You have a blood alcohol concentration (BAC) of 0.08% or higher.
  2. You are driving a commercial vehicle with a BAC of 0.04% or higher (see Commercial Drivers License Suspension in San Diego for more information).
  3. You are addicted to drugs.
  4. You are under the influence of alcohol, drugs, or both.


In order to find you guilty of a DUI in California, the prosecutor must prove, beyond a reasonable doubt, that you were in physical control of a motor vehicle and that you had a blood alcohol concentration (BAC) of 0.08% or higher at the time.


Penalties for a first-time DUI depend on a number of factors, including the circumstances of your case, your particular judge, and your prosecutor. A conviction for a first offense DUI involving no death or bodily injury typically mandates, but is not limited to, the following.

  • A fine of between $390 and $2,000, which includes penalty assessments.
  • The successful completion of an alcohol treatment program. If your BAC was at or below 0.2%, you are required to attend the program for 9 months.
  • A jail sentence of 48 hours.
  • Suspension of your drivers license for a minimum of 30 days, followed by driving restrictions (you may request a restricted license, which only allows you to drive to and from work and your alcohol treatment program).

A DUI attorney can help

When faced with a DUI for the first time, its crucial to avoid either a felony or a misdemeanor conviction. An experienced San Diego criminal defense attorney, with expert knowledge of DUI cases, will help you navigate the legal system and ensure the best possible outcome.

San Diego DUI Attorney specializes in DUI and criminal defense law, serving clients in San Diego, Vista, El Cajon, Oceanside, Chula Vista, and other San Diego County communities.

Contact our office today at 619-535-7150 for a FREE DUI consultation.


1 People v. Ramirez, 59 Cal. App. 4th 1548; People v. Jones, 126 Cal. App. 3d 308 2 Terry v. Ohio, 392 US 1, 20.
3 United States Constitution, Amendment IV

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