Case Title: State v. Hanks

Citation: 172 Vt. 93, 772 A.2d 1087

Docket Number: 99-490

State: vermont

Court: Vermont Supreme Court

Date: 2001-03-02T00:00:00Z

Document:
State v. Hanks  (99-490); 172 Vt. 93; 772 A.2d 1087

[Filed 02-Mar-2001]

       NOTICE:  This opinion is subject to motions for reargument under
  V.R.A.P. 40 as well as formal  revision before publication in the Vermont
  Reports.  Readers are requested to notify the Reporter of  Decisions,
  Vermont Supreme Court, 109 State Street, Montpelier, Vermont 05609-0801 of
  any  errors in order that corrections may be made before this opinion goes
  to press.

                                 No. 99-490

State of Vermont                               Supreme Court

                                               On Appeal from
     v.	                                       District Court of Vermont,
                                               Unit No. 3, Caledonia Circuit

Richard K. Hanks, Jr.                          September Term, 2000

Walter M. Morris, Jr., J.

       Robert Butterfield, Caledonia County Deputy State's Attorney, St.
  Johnsbury, for Plaintiff-Appellee.

       David J. Williams of Sleigh & Williams, St. Johnsbury, for
  Defendant-Appellant.

PRESENT:  Amestoy, C.J., Dooley, Morse, Johnson and Skoglund, JJ.

       JOHNSON, J.   Defendant appeals his jury conviction on a charge of
  driving while under the  influence of intoxicating liquor (DWI), in
  violation of 23 V.S.A. § 1201(a)(2).  He argues that the  district court
  erred by limiting his cross-examination of the state chemist so that he was
  prevented  from challenging the State's reliance on a permissive inference
  that his breath test result indicated he  was intoxicated.  We conclude
  that the trial court abused its discretion by refusing to allow defense 
  counsel to cross-examine the state chemist concerning the potential
  variability among different  persons at different times in the conversion
  rate between their breath-alcohol (BrAC) and blood-alcohol (BAC)
  concentration.  Because we cannot be sure that the error was harmless, we
  reverse the  conviction.

 

       Defendant was stopped and arrested for DWI in the early morning hours
  of September 30,  1998.  Approximately one hour and twenty minutes after
  the stop, defendant submitted a breath  sample that indicated a
  concentration of .109 grams of alcohol per 210 liters of breath.  Defendant 
  was charged with driving "under the influence of intoxicating liquor," in
  violation of 23 V.S.A.  § 1201(a)(2), rather than driving with an alcohol
  concentration of .08 or more, in violation of  § 1201(a)(1).  Nevertheless,
  the State indicated that it intended to introduce defendant's breath test 
  result to take advantage of the permissive inference that defendant was
  intoxicated at the time of the  alleged offense.  See 23 V.S.A. § 1204(2)
  ("If the person's alcohol concentration at [the time of  operation] was
  0.08 or more, it shall be a permissive inference that the person was under
  the  influence of intoxicating liquor in violation of section 1201(a)(2)");
  id. § 1204(3) ("If the person's  alcohol concentration at any time within
  two hours of the alleged offense was 0.10 or more, it shall  be a
  permissive inference that the person was under the influence of
  intoxicating liquor in violation  of section 1201(a)(2)").

       A jury trial was scheduled for September 28, 1999.  The day before
  trial, the State filed a  motion in limine asking the court to limit
  defense counsel's cross-examination of the State's expert  witness, a
  Department of Health chemist who was expected to explain the results of
  defendant's  breath sample.  The State asked the court "to exclude any
  examination based on variations as a  general matter in the human
  population in the so-called 'partition ratio.'"

       The "partition ratio" refers to the conversion rate between a person's
  BrAC and BAC.   Alcohol in the breath does not cause intoxication.  Rather,
  it is the impact of alcohol on the central  nervous system, particularly
  the brain, that causes the physiological and psychological changes 
  associated with impairment.  Alcohol reaches the central nervous system
  through the blood.  When 

 

  used to establish blood-alcohol levels, breath-testing devices such as the
  Datamaster machine use a  mathematical constant to approximate the
  percentage of alcohol in the blood based on the amount of  alcohol present
  in a breath sample.  Like other breath-testing machines, Datamaster uses a 
  conversion rate of 2100:1 as an assumed blood-breath ratio, which
  represents the relationship  between the number of alcohol molecules in the
  bloodstream to the number present in the breath  when both substances are
  tested simultaneously.  Thus, a 2100:1 conversion factor assumes that for 
  each molecule of alcohol in a given volume of breath, there are 2100
  molecules of alcohol in the  same volume of blood.

       It is generally recognized, as confirmed by the proffered testimony of
  the state chemist in the  instant case, (FN1) that "[b]ecause blood-breath
  ratios vary both between individuals, and at  different times in the same
  individual, a breath test based on a 2100:1 blood-breath ratio may not 
  accurately represent a particular individual's blood alcohol level."  State
  v. Brayman,