Anne ImObersteg and Associates provides consultation and testimony on all aspects of driving under the influence of alcohol or drugs. She testifies regularly on the effects of alcohol, theraputic/prescription drugs, and illegal drugs, on physical performance and/or driving behaviour.

In alcohol-related cases, the questions most asked in court revolve around the determination of the alcohol level of the driver at the time of the driving, the reliability of test results (breath alcohol testing device or Gas Chromatograph), the evaluation of any psychophysical roadside tests(FSTs), and possible impairment issues. Drug-related questions revolve around drug recognitions examinations, the analytical test results, the duration of drug action, the determination of influence, and possible driving impairment issues.

DRIVING UNDER THE INFLUENCE OF ALCOHOL

Determination of the driver's blood alcohol level at the time of driving is of prime importance. There are many factors which affect the reliability of the calculation, unique to each case, which must be considered. Generally speaking, however, by using the well-accepted Widmark formula, experimental averages, and relying on data from decades of research in this area, an expected blood alcohol level may be predicted.

Analytical results obtained from breath and blood testing devices must be carefully evaluated. A machine's reliability may be greatly affected by the manner in which it is used or maintained. Even in the best machines, operated properly, there exists a statistical inherent +/- margin of error.

Field sobriety tests are fairly simple to administer, yet difficult to interpret. One problem which plagues the reliability of field sobriety tests(FSTs)is the lack of standardization. Standardization helps make the administration and evaluation of a performance more objective rather than subjective.

Since 1977 efforts have been made to make the FST more objective rather than so subjective(Psychophysical Tests for DWI Arrest Final Report, DOT-HS-802-424, NHTSA ,1977). The National Highway Traffic Safety Administration (NHTSA)evaluated a myriad of field sobriety tests, and selected the walk and turn, nystagmus, and one-leg stand for standardization. NHTSA standardized the administrative procedures to be used, standardized clues to note, and standardized criteria for evaluation. Field testes performed in the NHTSA manner are termed SFST, or standardized field sobriety tests.

There is controvery among forensic scientists as to the true reliability of the SFST to predict a particular blood alcohol level or driving impairment. Indeed, even the NHTSA studies have conceded that performance on the SFST is not a direct indication of driving impaiment. In 1981, Seaver & Schwartz came to the inevitable conclusion that "...even valid, tests are likely to be poor predictors either of actual behind-the-wheel driving or of accidents."(An Assessment of Behavioral Tests to Detect Impaired Drivers, Final Report,DOT-HS-806-21.)

This conculsion should not be surprising to most scientists: once field sobriety testing is taken out of the laboratory and into the field, there is no ability to control the variables which influence physical and mental performance.

Some variable include:
1) Lack of a baseline makes interpretation difficult; there is no comparison from which to determine if there is a change in normal performance due to alcohol.
2) Medical problems influence performance;illnesses which affect balance and coordination will impact performance
3) Environment influences performance; distraction from passing traffic, weather, ground surface characteristics etc.
4) Situational issues influence performance; fear, nervousness, fatigue etc.
5) Not all tests have been evaluated for reliability or criteria for interpretation; hand pat, alphabet, finger-to-nose etc.
6) Interpretation may be subjective, and not based on objective criteria
7) Tests are often not administered and evaluated in the manner required by NHTSA
8) Age, weight, and fatigue play an important role in physical and mental abilities
9) Some individuals find these tests to be difficult to perform in normally
10) The Federal studies have admitted that there is no direct correlation between a particular performance on a SFST with driving impairment.

DRIVING UNDER THE INFLUENCE OF DRUGS

The burden of identifying signs and symptoms of drug abuse predictably falls on the police officer. Thus, the officer’s ability to correctly recognize and identify the signs and symptoms of drug use and abuse in traffic situations is critical.

Historically, police officers used a variety of random methods and tests to assist in the determination of influence. Many of these tests were poorly administered or misinterpreted. Understandably, this subjective process was prone to error.

Spearheaded by the efforts of the Los Angeles Police Department, a systematic and standardized procedure was developed in the 1980s to assist police officers in determining drug influence. The theory behind the process is that each drug category produces typical effects which may become evident with the administration of a standardized series of steps.

In 1984, The National Highway Traffic Safety Administration (NHTSA) announced that it supported the Los Angeles Police Department’s program. Subsequently, in 1987/1988, the International Association of Chiefs of Police (IACP) was requested by NHTSA to develop a standardized Drug Evaluation and Classification (DEC) program which could become the national standard for all drug recognition programs.

The DEC process assists the evaluator in classifying the suspected drug into seven broad categories, based on the similarity of the observable signs generated during the examination. The seven categories are:
1. Phencyclidine
2. CNS Stimulants such as cocaine and methamphetamine
3. Inhalants such as solvents, aerosols and anesthetic gases
4. CNS Depressants such as alcohol, diazepam etc.
5. Cannabis (marijuana)
6. Hallucinogens such as psilocybin and LSD
7. Narcotic analgesics such as heroin and codeine

The Drug Recognition Expert (DRE) observes and documents a variety of signs and symptoms of drug use broken into a series of “steps”. By following the twelve steps, the DRE may be able to determine whether the signs and symptoms observed were consistent with any of the seven categories of drugs evaluated. The twelve steps are:
1. The Breath Alcohol Test
2. Interview with the Arresting Officer
3. The Preliminary Examination
4. The Eye Examination (nystagmus)
5. Divided Attention Psychophysical Tests
6. Dark Room Evaluation (pupil size)
7. Vital Signs Examination
8. Examination for Muscle Rigidity
9. Examination for Injection Sites
10. Suspect’s Statements and Other Observations
11. Opinions of the Evaluator
12. The Toxicological Examination

After information is gathered, the forensic toxicology or pharmacologist is asked in court to evaluated the data gathered in the twelve steps. The expert must determine if the signs and symptoms documented are sufficient and/or consistant with influence. If there is influence, the expert must then review scientific and case-specific data to support driving impairment.

Such a determination is not simple. It is well known that mere presence of the drug in a tested body fluid does not automatically mean the person is legally under the influence. In fact, drugs can be detected in the body a day or weeks after the active effects of the drug have dissipated. Consider:

Does the scientific literature support driving impairment?
Does the person have TOLERANCE for the drug?
Is the driver actually
Is there literature citing driving IMPROVEMENT?
What drug are we dealing with?
Are some signs seen inconsistant with the suspected drug?
Are there other reasons for the signs seen?
Could fight/flight/fright response cause the signs seen?
Was a urine or blood sample taken?
What are the statements of the Defendant?
How was the Defendant driving?
What kind of drug recognition examination was performed?
How does the laboratory analysis look?