Distracted driving under Vehicle Code 23123.5, mainly using a handheld phone, is a frequent reason for a traffic stop, and that stop sometimes turns into a DUI investigation. I am Joel Brand, and here is what the statute prohibits and how it factors into a DUI case.
The text of the law
Vehicle Code 23123.5. (a) A person shall not drive a motor vehicle while holding and operating a handheld wireless telephone or an electronic wireless communications device unless the wireless telephone or electronic wireless communications device is specifically designed and configured to allow voice-operated and hands-free operation, and it is used in that manner while driving. (b) This section shall not apply to manufacturer-installed systems that are embedded in the vehicle.
What the statute prohibits
The law bars "holding and operating" a handheld phone or electronic device while driving. The device generally must be mounted and used hands-free. The two operative words, "holding and operating," matter: the statute targets holding the device in your hand and using it, not every conceivable contact. Case law has further limited it, holding that merely glancing at a mounted phone or using a single tap or swipe in a mounted configuration is treated differently than holding the phone and operating it. A violation is an infraction; a second offense within 36 months adds a point to your record. A separate statute, Vehicle Code 23124, applies stricter rules to drivers under 18, who may not use a wireless device at all while driving, even hands-free. For most adult drivers, though, the holding-and-operating standard of 23123.5 is what controls, and it is narrower than officers sometimes assume.
The observation is easy to get wrong
An officer who believes a driver is on a phone may use that as the reason to initiate a stop. But the observation is frequently mistaken. From outside a moving car, at night, it is easy to confuse a mounted phone, a hands-free interaction, a hand near the face, eating, or simply resting a hand, with prohibited handheld use. Whether the officer actually saw "holding and operating," as the statute requires, is often genuinely debatable.
Why it matters in a DUI
In a DUI, the distracted-driving observation is usually the officer's stated justification for the stop. If that observation does not amount to a violation, for instance because the phone was mounted or you were using it hands-free, the basis for the stop is in question. And if the stop was unlawful, the evidence gathered afterward can be suppressed, which is exactly why this small infraction can matter to the whole case.
Challenging the stop
When phone use is the basis for the stop, I look closely at what the officer actually claims to have seen and whether it meets the holding-and-operating standard, comparing it to any video. Where the claimed violation does not hold up, I bring a motion to suppress under Penal Code 1538.5. Suppressing the stop can unravel the DUI, because everything the state has flows from that initial contact. I request the officer's vantage point, the lighting, and any video precisely to test whether a genuine holding-and-operating observation was even possible, since an assumption is not the same as an observation, and a stop built on a guess about what a driver's hand was doing is exactly the kind of stop that does not survive scrutiny.
The mounted-phone and hands-free exceptions
The statute and the cases interpreting it carve out real space for lawful use. A phone mounted on the dash or windshield and operated by voice or a single touch is generally permitted, and manufacturer-installed embedded systems are expressly exempt under subdivision (b). Many drivers cited under 23123.5 were actually using their phones in a lawful, mounted, hands-free way, and establishing that defeats both the infraction and the stated reason for the stop.
Points, fines, and the record
The base offense is a fine, with a higher fine and a point for a repeat within three years. On its own it is minor, but when it accompanies a DUI it adds to the record and can be folded into the overall resolution. As with the other traffic stubs, keeping any point off your record matters for insurance and the DMV's negligent-operator thresholds.
Phone use is not impairment either
As with the other traffic stubs, it is worth separating the two ideas. Using a phone while driving, even unlawfully, is not evidence that you were impaired by alcohol or drugs. Distracted driving and impaired driving are different problems with different proof. An officer who saw what they believed was phone use cannot use that to fill gaps in the impairment case. I keep the distracted-driving allegation in its lane, so to speak, and require the prosecution to prove impairment independently rather than letting a phone observation color the whole case.
How these cases resolve
The distracted-driving count itself is usually a small part of a combined case. The realistic goals are to dismiss the infraction where the mounted or hands-free defense applies, to keep any point off your record, and to fold the citation into the overall resolution of the DUI. The far more valuable outcome is using a weak phone-use observation to attack the stop itself, because if the stop falls, the DUI often falls with it. That is where I put the emphasis.
How it fits the larger defense
The distracted-driving issue is one piece of attacking the lawfulness of the stop, the most powerful category of DUI defense. It works alongside challenges to the field sobriety testing and the chemical evidence, and it can reveal broader police mistakes at a DUI stop. See my top DUI defenses and the defenses guide.
Stopped for phone use and arrested for DUI? Let's talk.
Whether that stop was justified may decide your case, and it is exactly what I review. Use the free case analysis on this page, or call me directly at (888) 271-6644. I answer my own phone, 24 hours a day, 7 days a week.