San Diego DUI Law Center

“Reasonable Cause” – the 1st DUI Issue in a DMV Hearing

The first California DMV administrative per se hearing issue which San Diego attorneys challenge after a DUI arrest is “reasonable cause.”  DMV’s evidence must be sworn.  There are numerous challenges which can be reasonably made.  DMV hearing officers are not lawyers; instead they at least partly rely on state drunk driving training and this DMV manual.


The first issue in an APS hearing is reasonable cause. Did the officer have reasonable cause to believe the person had been driving a motor vehicle in violation of §23152, §23153 VC, or §23136 and/or §23154 VC?

Reasonable cause means something more than a mere hunch or suspicion, but less than the amount of evidence needed for proof beyond a reasonable doubt. The officer does not need conclusive evidence of criminal guilt. The facts known to the officer must lead a “reasonable person” with the same facts, to conclude the person was driving a motor vehicle while under the influence. Would a person of “ordinary care and prudence” believe that the driver was guilty?

Reasonable cause has the following components or sub-issues which all must be present and established by evidence if a positive finding is made on the issue. These components all deal with the peace officer’s beliefs about the person under investigation.

The officer must have:
• Reasonable cause to believe the person was driving a motor vehicle.
• Reasonable cause to believe the person was under the influence of alcohol and/or drugs.
• Reasonable cause to believe the person was driving while under the influence.

Each component of the reasonable cause issue operates separately and evidence supporting (or not supporting) each component should be separately established. For example, there may be substantial evidence to show a person was under the influence, but insufficient evidence to establish driving. A person may have driven and admitted to having a drink, but the evidence is insufficient to show they exceeded the legal BAC limit.

In a typical example of proper reasonable cause, the officer, after contacting a driver, asked for the license and registration. The driver had great difficulty getting the license out of the wallet. There was the odor of alcohol on the breath, the eyes were bloodshot and glassy, and the speech was slurred and rambling. Getting out of the car, the driver fell against the officer and had to be supported. The totality of these circumstances allows any officer reasonable cause to further investigate the driver.”

The foregoing excerpts are from the updated DMV Administrative Per Se Hearings Manual [Chapter 12] for California DMV Hearing Officers, page 12-30.