San Diego DUI Law Center

“Rising” BAC (Blood Alcohol Concentration) DMV Resources

An alcohol level or Blood Alcohol Concentration result of a person does not stay the same all day or night.


DMV can only suspend if the person’s BAC was .08% or more at the time of driving.

According to DMV law, this issue is – “Were you driving a motor vehicle when you had 0.08% or more by weight of alcohol in your blood?” (emphasis added)

The relevant issue in “rising” cases is – what was the person’s true BAC at the time of driving?

If a person drank alcohol at a relatively short time prior to driving, that alcohol would not have been absorbed in the person at the time of driving.

Rather, that alcohol would take time to get into the person’s system.  The person’s BAC level would continue to increase until it is all absorbed sometime after drinking concluded.

If the person’s body is still absorbing the alcohol while driving, the person’s BAC level continues to increase or “rise.”

The person is always tested some time after driving.

If the person’s BAC level was still “rising” while driving, then the BAC result at the time of the test is higher than the person’s true BAC at the time of driving.

For example, a person who is “rising” –  with a reported .09% BAC at the time of the test – would have a lower BAC at the time of driving.

If an age 21 or over person’s BAC at the time of driving can preponderantly be .07% or less, then DMV must not suspend his or her driver’s license.

Minutes add up.  BAC levels change over hours.

The lower BAC at the time of driving depends on the times of drinking – especially when the person had his or her last drink –  in relation to the time the person stopped driving.

The lower BAC at the time of driving also depends on how many drinks the person had in relation to his or her weight.

DMV publishes technical charts for this. For years, California drivers were mailed these charts* with licenses, registration tags and the like.  “HOW TO USE THESE CHARTS: Find your weight chart. Then, look for the total number of drinks you have had and compare that to the time shown.”

According to the white, gray and black boxes in DMV’s charts, depending on one’s weight, a person can preponderantly go from:

.01%-.04% in one hour, to

.05%–.07% in next hour, to

.08% or higher in the next hour.

Illustrations for “rising” persons as high as 189 pounds (or less) [using DMV’s BAC charts]:

A .08% test taken one hour after a person’s driving could mean his or her BAC was .07%, .06% or .05% at the time of driving.

A .08% test taken two hours later could mean his or her BAC was .04%, .03%, .02% or .01% at the time of driving.

A .11% test taken in the second hour could mean his or her BAC was .07% at the time of driving.

A .11% test taken in the third hour could mean his or her BAC was .04% at the time of driving.

In DMV administrative hearings arising out of California DUI arrests, the DMV must take official notice of any “generally accepted technical or scientific matter.”*

This includes the following generally accepted technical matter and summarized scientific evidence consisting primarily of Prosecutorial (Law Enforcement) scientific literature and independent scientific studies & writings by Dr. Dubowski and AW Jones, the most scientifically well-known alcohol experts in the world:

1.  DUI Law Enforcement Strategies:  Law Enforcement Officials on Administering Field Sobriety Tests, Interpreting Results, and Preparing for Court Testimony  (Inside the Minds) [ASPATORE Books]  “The Essential of DUI Assessment and Testing”:

“In most cases, alcohol is completely absorbed within one to one-and-one-half hours; however, in some case it may require almost three hours for total absorption.”


Taught By Fred Tulleners & Craig Anderson, Department of Justice Bureau of Forensic Services:

“As a general rule only, complete absorption of a single alcoholic beverage is usually accomplished in from forty-five minutes to an hour, with an empty stomach.”  (page 5-5)


by Kurt M. Dubowski, Ph.D.:

“…alcohol absorption is not always complete within 60 to 90 min, as often claimed.” (Journal of Studies on Alcohol, Supplement, page 106)

Dr. Dubowski found that elapsed time from end of alcohol intake to peak blood alcohol concentration varying from 14 to 138 (2hrs. 18 min) minutes, a nearly 10-fold variation.  [Download PDF here]

4.  “Food-Induced Lowering of Blood-Ethanol Profiles and Increased Rate of Elimination Immediately After a Meal

by A. W. Jones:

“Consumption of alcohol with food can increase alcohol clearance by 1-2 hours, and increase the rate of alcohol metabolism by between 36% and 50%, as compared to consumption on an empty stomach.”

[ A. W. Jones, Food-Induced Lowering of Blood-Ethanol Profiles and Increased Rate of Elimination Immediately After a Meal , Journal of Forensic Sciences 1994 July; 39(4):1084-1093, p. 1084; see also ATTACKING AND DEFENDING DRUNK DRIVING TESTS by Donald J. Bartell, Mary Catherine McMurray & Anne D. ImObersteg, page 2-7]

5. “Interindividual Variations in the Disposition and Metabolism of Ethanol in Healthy Men”

by A. W. Jones:

“In one study, peak alcohol concentration ranged from 30 to 120 minutes…”

“…25 of the subjects took between 60 and 120 minutes to reach peak absorption.”

(A.W. Jones,  “Interindividual Variations in the Disposition and Metabolism of Ethanol in Healthy Men”, Alcohol 1984 Sept-Oct;1(5):385-91, at p. 385.)

6.   A Google Map, Yahoo Map or MAPQUEST shows the distance between the DUI police stop location and the place where alcohol was drank, e.g. as reported by the subject California DUI arrest report offered by DMV as evidence.  These Internet maps are generally accepted technical evidence.

A California DUI arrest report is usually offered by DMV as evidence.  It reports the location of the DUI arrest (e.g. on page 1) and any police interview of the driver or reported statements relating to where the person had been drinking alcohol.

In San Diego, California DMV serves the Respondent driver’s attorney a REQUEST FOR DISCOVERY “…including any statements, writings…or things which are relevant to this proceeding.”

Respondent has a right to adequately prepare and present evidence at the hearing  [California Government Code 11507.6].

Respondent has a due process right to present evidence  [Govt Code 11425.10].

Respondent has a due process right to rebut evidence  [Govt Code 11425.10].

* California Government Code Section 11515 requires the California Department of Motor Vehicles to take “official notice…of any generally accepted technical or scientific matter within the agency’s special field, and of any fact which may be judicially noticed by the courts of this state.”

California Evidence Code Section 452(g) permits the Department to further take official notice of facts and propositions that are of such common knowledge within the territorial jurisdiction of the court that cannot reasonably be the subject of dispute.  There should be no dispute as to the path of travel between these locations.

California Evidence Code Section 452(h) further permits the Department to take official notice of facts and propositions that are not reasonably subject to dispute and are capable of immediate and accurate determination by resort to sources of indisputable accuracy.  An Internet map is subject to easy verification.  This immediate determination of accuracy can be done by the Department.

In addition to the above California Government and Evidence Code sections, hearsay evidence may be solely relied upon in a decision in favor of the driver.  This is because Govt. C. Section 11513(c) does not expressly limit the manner in which a licensee’s (driver’s) evidence may be considered.  [Robertson v. Zolin (1996) 44 Cal.App.4th 147, 151]

DMV’s technical BAC/absorption chart (a state publication), law enforcement absorption science (prosecutorial publication), DMV scientific/technical absorption training manual (DOJ publication),  independent expert conclusions relating to alcohol absorption (generally accepted scientific studies), and/or Internet maps (generally accepted technical matters) are all examples of officially noticed evidence considered by a DMV hearing officer or San Diego California Superior Court.

The law requires DMV to consider these officially noticed matters or evidence in fairly determining whether or not to suspend a person’s driving privileges when his or her BAC level is reasonably rising at the time of driving.

If a preponderance of the evidence supports a finding that the person’s BAC was:

a) not .08% or more at the time of driving, or

b) .07% or less at the time of driving,

DMV will grant a California DUI lawyer’s request to set aside the suspension action.

* Recently, DMV changed their charts. They stopped using time of drinking or HOURS in their charts.

Instead of determining one’s level based on number of drinks and number of hours, they now determine .08% or more based on number of drinks and body weight in pounds.

DMV DL 606 (REV. 7/2010) now says:

“Get a DUI – Lose Your License!

It is illegal to drive with a Blood Alcohol Content (BAC) of .08% or more (.04% for commercial vehicle drivers and .01% if under 21). Other factors, such as fatigue, medications or food may affect your ability to legally operate a vehicle. The table below gives an estimate of blood alcohol levels based on the number of drinks, gender and body weight. REMEMBER: Even one drink is likely to affect your ability to drive safely!

Subtract .01% for each 40 minutes of drinking.
1 drink = 1.5 oz. 80 proof liquor, 12 oz. 5% beer, or 5 oz 12% wine.
Fewer than 5 persons out of 100 will exceed these values.”

Why has DMV stopped using their charts which would help drivers try to calculate their BAC depending on how long they have been drinking (e.g. 2 or 3 hours)?

Why does the new DMV chart or table not take into account the passage of time in terms of hours of drinking?

How can DMV distribute a chart which incorrectly suggests that you lose your license if you “get a DUI” when the issue is whether the driver’s BAC is .08% or more at time of driving?

Why would DMV suggest, e.g., that a 140 pound male would have have a BAC of .17% (over twice the legal limit) after just 4 drinks without any reference to the number of hours of drinking?