If you or a loved one is facing an allegation of DUI vehicular manslaughter, you’re dealing with one of the most emotionally heavy and legally serious situations that can come out of a traffic stop or collision. The fear is immediate: prison, a felony record, license loss, and life-changing consequences—all while trying to process what happened.
In California, the charge most commonly tied to “DUI manslaughter” is Penal Code 191.5(b), known as vehicular manslaughter while intoxicated with ordinary negligence. It’s crucial to understand this: a PC 191.5(b) case is not “just a DUI.” The prosecution has to prove additional elements, including negligence and causation, and those elements can be challenged with evidence, timelines, and expert analysis.
What Is DUI Vehicular Manslaughter Under PC 191.5(b)?
Under Penal Code 191.5(b), vehicular manslaughter while intoxicated is generally described as an unlawful killing without malice aforethought that occurs while driving a vehicle in violation of certain DUI laws (including California Vehicle Code DUI statutes), where the death is alleged to have resulted from an unlawful act that is not a felony, or from a lawful act performed in an unlawful way—but without gross negligence.
A few practical takeaways flow from that definition. First, the case involves a death, which automatically raises the stakes and changes how prosecutors approach charging and negotiation. Second, the driving is alleged to involve a DUI violation, meaning the prosecution will typically build the case around DUI evidence plus what they claim happened in the driving conduct itself. Third, the prosecution must prove negligence—ordinary negligence for PC 191.5(b)—and must also prove causation, meaning the alleged negligent conduct was a cause of the death. Those two issues—negligence and causation—are often where many defenses are built.
This page and website provide general information in plain English, not legal advice. Laws and local court/DMV practices vary and can change, so don’t rely on this content for your case—talk to a qualified attorney promptly to review your specific facts, especially if you face charges, a DMV action, or a deadline. In many cases, you’re fighting two battles at once: the DMV process and the criminal court case.
PC 191.5(a) vs. PC 191.5(b): Gross vs. Ordinary Negligence
California separates DUI manslaughter cases into two primary categories based on the level of negligence the prosecution claims.
PC 191.5(a) is gross vehicular manslaughter while intoxicated. This version alleges DUI plus gross negligence, is punished more harshly, and is typically treated as a felony with greater sentencing exposure.
PC 191.5(b) is vehicular manslaughter while intoxicated based on ordinary negligence. This version still alleges DUI, but it relies on a lower negligence standard than “gross,” and that distinction can matter in real cases because it affects how the case is charged, how plea negotiations unfold, the potential sentencing range, and trial strategy.
Early defense work often focuses on whether the facts actually support a gross-negligence theory, or whether the evidence fits—at most—ordinary negligence, or does not meet the required standard at all.
What the Prosecutor Must Prove (Elements)
A helpful way to understand the “moving parts” of a PC 191.5(b) case is the Judicial Council’s jury instruction outline (CALCRIM 591). In general terms, to prove vehicular manslaughter with ordinary negligence while intoxicated, the prosecution must show that you were driving under the influence (or with a qualifying BAC, depending on the theory). The state must also prove that, while driving under the influence, you committed a misdemeanor or infraction, or performed an otherwise lawful act in a way that might cause death. Beyond that, the prosecution must prove you committed the act with ordinary negligence, and that your negligent conduct caused the death of another person.
That is a lot more than “you had alcohol in your system.” Each required element is a target for a careful, evidence-based defense, especially where the facts are disputed or the state’s theory depends on assumptions about what “must have happened.”
“Ordinary Negligence” Explained in Plain English
Many people hear the word “negligence” and assume it automatically means guilt. It doesn’t. Ordinary negligence is about whether reasonable care was used under the circumstances, not whether someone intended harm.
CALCRIM 591 describes ordinary negligence as failing to use reasonable care to prevent reasonably foreseeable harm. A person may be considered negligent if they do something a reasonably careful person would not do, or fail to do something a reasonably careful person would do, in the same situation. That matters because ordinary negligence is not “evil intent,” and it is not automatically proven simply because there was a collision. Real cases can involve unclear road conditions, unexpected maneuvers by other drivers, mechanical issues, limited visibility, or multiple contributing factors that complicate what “reasonable care” looked like in that moment.
A defense may focus on showing your driving conduct was not negligent under the circumstances, that the alleged negligent act was not proven, or that the state cannot prove causation beyond a reasonable doubt.
Causation: Did the Alleged Negligence Actually Cause the Death?
In a fatal crash case, causation is often the central battleground. Even when the prosecution alleges DUI and points to a driving error, the state still has to prove that the alleged negligence actually caused the death in a legally meaningful way.
CALCRIM 591 explains key causation concepts, including that the death must be the “direct, natural, and probable consequence” of the act, and that while there can be more than one cause of death, the defendant’s act must be a substantial factor—more than trivial or remote. In real cases, that’s where accident reconstruction, timelines, medical evidence, and scene facts can become decisive, because the prosecution’s causal story has to match what the evidence shows.
Causation disputes often turn on concrete questions. Was the death caused by the collision itself or by something that happened after the collision? Were multiple vehicles or actions involved? Did another driver’s conduct—speeding, an unsafe lane change, or a red-light violation—contribute in a way that breaks or complicates the causal chain? Did road design, lighting, weather, or signage play a meaningful role? And are the injuries truly presented with the certainty the state claims, or is the prosecution overstating what would have happened “even with perfect driving?”
A strong defense does not assume causation. It tests causation with evidence.
Common Evidence in DUI Manslaughter Cases
A PC 191.5(b) case often involves a large volume of evidence generated quickly after the incident. The file typically includes a collision report with diagrams and measurements, photos of the scene and vehicle damage, and bodycam or dashcam footage that may confirm or contradict key claims. Prosecutors may rely on witness interviews as well, even though accounts are often inconsistent in chaotic events, and the case may include 911 calls and dispatch logs that help establish timing and what was reported in real time.
On the DUI side, breath results may appear if taken, but blood testing is very common in serious collisions, and those results are often supported by hospital records and toxicology documentation. Some cases also involve event data recorder (“black box”) data and, when distracted driving is alleged, phone records. Timeline evidence matters throughout, including driving time, impact time, police contact, and testing time, because the state often tries to build the impairment narrative around that sequence.
Because so much evidence is created and distributed quickly, early defense work often focuses on preservation and review—video, data, lab documentation, and collision analysis—so the defense can evaluate what the evidence actually proves and where reasonable doubt exists.
How We Fight DUI Charges
DUI defense is evidence defense. We build your case by examining every step of the DUI process and looking for errors, weaknesses, and contradictions—because DUI cases are won by details, not assumptions.
Challenge the DUI proof
Even in a manslaughter case, DUI still has to be proven, and that proof depends on the theory the state is using. The prosecution may claim alcohol impairment, a BAC-based DUI, drug impairment, or combined alcohol and drugs. If the DUI evidence is weak, inconsistent, or procedurally flawed, the foundation of the entire case changes because the state loses the starting point it needs to connect the driving conduct to criminal liability.
Attack chemical testing (breath/blood)
Chemical testing is often treated as objective proof, but it can be challenged on procedure, timing, documentation, and reliability. Breath testing issues may involve maintenance and calibration history, operator procedure, observation-period problems, and medical explanations that can distort results. Blood testing issues may involve chain of custody, storage and preservation, contamination or fermentation risk, lab protocol and documentation problems, and interpretation—especially when the state tries to use presence of a substance as a shortcut to impairment.
Contest “ordinary negligence”
A PC 191.5(b) case requires proof of ordinary negligence tied to a specific unlawful act, or a lawful act performed in an unlawful way. Defense work often begins by identifying what the prosecution claims the “predicate act” actually was and then challenging whether that act is supported by the evidence. The defense may also show the driving choice was reasonable under the circumstances—especially where the facts suggest an emergency, unclear conditions, or split-second decision-making. In many cases, the prosecution’s collision narrative rests on assumptions, and those assumptions can be tested against measurements, video, vehicle damage patterns, and timing.
Contest causation with facts and experts
Causation is often where prosecutors feel most confident, but it’s also where a prepared defense can create real doubt. Defense work may include an independent accident reconstruction review, speed and timeline analysis, and medical causation review to evaluate whether the alleged negligent act was truly a substantial factor in the death. Many fatal collisions involve multiple contributing factors, and a strong defense identifies alternative explanations the state may be ignoring or oversimplifying.
Build trial-ready leverage (even if the goal is resolution)
In serious cases, meaningful negotiations usually come from being ready to challenge the government’s proof—not from hoping for leniency. Trial readiness can influence charging decisions, plea offers, and sentencing advocacy because it signals that the defense can and will test every part of the state’s case if needed.
Penalties and Sentencing Exposure (Overview)
Penal Code 191.5 includes specific sentencing provisions. For PC 191.5(b), the statute states it is punishable by county jail for not more than one year, or by imprisonment pursuant to PC 1170(h) for 16 months, two years, or four years.
That’s why people often describe PC 191.5(b) as a “wobbler” in practice—the charging and sentencing posture can vary based on the facts, the alleged negligence, causation issues, and record history.
Also important: PC 191.5 has a much more severe provision for certain defendants with specified prior convictions, where a person convicted of PC 191.5(a) with qualifying priors “shall be punished” by 15 years to life, and those prior-conviction facts generally must be alleged and admitted or found true. Whether any special allegation applies is case-specific and depends entirely on the record and what is actually charged.
DMV and License Consequences After a Fatal DUI Arrest
Even while the criminal case is pending, your license may be at risk through separate DMV action, and the deadlines can move fast. California DMV guidance explains that hearings must be requested within 10 days of receiving notice (or 14 days from the date of the notice if the notice was mailed), or you may forfeit hearing rights.
In a serious case, coordinating the DMV strategy with the criminal defense strategy is critical because timelines, statements, and evidence positions can overlap.
What to Do Immediately After a Fatal DUI Arrest
If the incident is recent, what you do in the first days can materially affect both the criminal case and your license status. In fatal cases, early decisions often shape the trajectory of the entire matter, which is why hiring experienced counsel immediately is critical—so evidence can be preserved, deadlines identified, and a strategy can be built before the government’s narrative hardens.
Just as important, do not discuss details with anyone other than your attorney. That includes friends, insurance adjusters, social media, and even casual conversations, because statements can be repeated, misunderstood, or taken out of context and then used against you in both criminal and civil proceedings.
While your memory is fresh, write down your timeline in one place: where you were, what you ate or drank, any medications, sleep, your driving route, time stamps, and everything you remember about the moments leading up to the impact. In serious cases, timelines often become a key battleground, and accurate early notes can be helpful later when records, reports, and test times are compared.
You should also preserve anything you can. Receipts, phone GPS history, photos, vehicle paperwork, tow and storage information, and the names and contact details of witnesses can all matter, especially when the case turns on causation, speed, timing, or what actually happened at the scene.
Finally, address DMV deadlines quickly. DMV hearing rights can expire fast depending on the notice you receive, and protecting your ability to keep driving—or at least preserving the right to challenge a suspension—often requires immediate action.
PC 191.5(b) Frequently Asked Questions
Is “DUI manslaughter” the same as murder?
No. PC 191.5(b) is manslaughter “without malice.” The statute also says it does not prevent a murder charge under certain facts (implied malice / Watson theory), but that’s a different legal pathway and depends on case-specific facts.
What’s the difference between PC 191.5(a) and 191.5(b)?
The key difference is the degree of negligence (gross vs ordinary). The jury instruction for 191.5(b) is built around ordinary negligence plus DUI plus causation.
Can causation be disputed if a death occurred in the crash?
Yes. The state must prove your negligent conduct caused the death, and causation can involve substantial-factor analysis and multiple contributing causes.
What’s the sentencing range for PC 191.5(b)?
The statute provides for up to a year in county jail, or 16 months / 2 years / 4 years under 1170(h), depending on how the case is charged and sentenced.