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Timing: How California’s DUI Presumption Works Under Vehicle Code § 23610 and People v. Schrieber In California DUI cases, the l

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The Timing Trap: How California’s DUI Presumption Works

(Vehicle Code § 23610 and People v. Schrieber)

In California DUI cases, the legal effect of a chemical test result depends not only on the number, but also on when and how that number was obtained. Two frameworks often get conflated: (a) the per se offense of driving with a blood alcohol concentration (BAC) of 0.08 percent or more, and (b) the evidentiary presumption that a driver was “under the influence” if the BAC is 0.08 percent or more. Vehicle Code § 23610 addresses the latter, and its timing mechanics differ in important ways from the per se statute.

Statutory Presumptions Under Vehicle Code § 23610

Vehicle Code § 23610 permits a jury to presume that a defendant was under the influence if a qualifying chemical test shows a BAC of 0.08 percent or more. Critically, unlike the statute defining the per se offense of driving with a 0.08 percent BAC or more, § 23610 does not impose a specific time limit for when the chemical test must be administered to trigger the presumption. That absence of an explicit temporal window matters: it means the presumption can apply without a bright-line cutoff such as “within two or three hours” of driving, so long as the test result is otherwise admissible and tied to the alleged driving.

People v. Schrieber (1975): Incidental to the Offense and the Arrest

In People v. Schrieber (1975), the court addressed the mandatory testing statute and emphasized two limiting principles tied to timing and sequence:

  1. The test must be incidental to the offense.
  2. The test must be incidental to the arrest.

The court noted that no substantial time should elapse between the offense and the arrest. In other words, even though § 23610’s presumption does not itself specify a strict testing deadline, Schrieber underscores that the statutory testing scheme operates on a prompt-continuity model: the offense, the arrest, and the test should form a reasonably continuous chain. If that chain is broken by substantial delay between the offense and the arrest, the foundation for the test—and any presumption flowing from it—can be undermined.

Why Timing Still Matters Without a Fixed Test Window

The absence of a defined time limit in § 23610 does not make timing irrelevant. Instead, timing affects:

  • The logical link between the test result and the driver’s condition at the time of driving. The longer the delay, the more fertile the ground for rising BAC arguments, unabsorbed alcohol, or post-driving drinking claims.
  • The admissibility and weight of the evidence. A test obtained after an undue lapse—or not reasonably incidental to the offense and arrest—may face foundational challenges or diminished persuasive force before a jury.
  • The applicability and strength of the presumption. While § 23610 allows the presumption without a specified cutoff, Schrieber’s incidental-to-offense-and-arrest framework can limit or erode the presumption where the sequence or timing is not tight.

Practical Implications for DUI Litigation

  • Foundation and continuity: Establish a clear, contemporaneous timeline that ties the observed driving to the stop, the arrest, and the test. Gaps invite challenges to both admissibility and presumption.
  • Rising BAC and absorption dynamics: In cases with notable delays, expert testimony on alcohol absorption and elimination can rebut or reinforce the presumption, depending on the facts.
  • Procedural scrutiny: Ensure compliance with mandatory testing requirements and demonstrate that the test was truly incidental to the offense and the arrest. Where substantial time elapsed, be prepared to litigate whether the Schrieber continuity requirement was satisfied.
  • Jury instructions strategy: Because § 23610 permits the presumption without a fixed testing window, parties should focus on how the timing evidence informs the jury’s evaluation of whether the result reflects the defendant’s condition at the time of driving.

Bottom Line

Even though Vehicle Code § 23610 does not impose a specific time window for administering a chemical test to trigger the under-the-influence presumption at 0.08 percent or more, timing remains pivotal. People v. Schrieber instructs that the test must be incidental to both the offense and the arrest, and that no substantial time should elapse between them. In close cases, the strength—or viability—of the presumption will often turn on how closely the prosecution can stitch together the timeline from driving to arrest to test, and how effectively the defense can expose breaks in that chain.

If you have a DUI call expert DUI attorney Daniel Horowitz to mount the most effective DUI defense.  Call (925) 283-1863.