From: Jim Rosenfield <[j n r] at [igc.apc.org]>
Newsgroups: talk.politics.drugs
Date: 12 Jan 94 18:04 PST
Subject: Drugs and Driving

/* Written  6:03 pm  Jan 12, 1994 by [j n r] at [igc.apc.org] in igc:norml.hemp */
/* ---------- "Drugs and Driving" ---------- */
DRAFT Executive Summary
13th California State Epidemiological Workshop
Group Report Meeting 10/9/93, Dep't of Alcohol and Drug Programs

     We are currently working on a project focusing on
     driving while under the influence of drugs, in addition
     to alcohol-related DUI.  

The 1988 Department of Justice Toxicology data show that 25% of
all DUI arrests involved drugs, either alone or in combination
with alcohol and other drugs.  The drugs identified, in order of
prevalence, included marijuana (detected in 16% of all DUI
toxicology tests); cocaine (detected in 9% of the cases); and
methamphetamine, PCP, and other drugs, which were each identified
in 6% or less of the cases.  Data also revealed that the lower
the blood/alcohol count (BAC) of an arrested DUI offender, the
greater the likelihood that drugs were involved.  For example,
arrested DUI offenders with BACs below .05% tested positive for
drugs 58% of the time, versus the 25% drug-positive test rate
among all DUI arrestees.  Because law enforcement officers
typically base their initial decision to stop a potential DUI
offender on the basis of observed erratic driving behavior and
have no knowledge at that time of what substance, if any, the
offender may be under the influence these data imply that drugs
impair driving ability in much the same observable manner as does
alcohol.  Unfortunately, our knowledge of the correlation between
drug levels and driving impairment is still rather limited.
     
Most studies that have investigated the relationship between
drugs and driving have focused on the correlation between drug
involvement and driving record.  For example, convicted drug
users had significantly more traffic violations but not traffic
accidents than did the average driver.  On the basis of these
data, it was speculated that conviction for drug use did not pose
any increased traffic safety risk.  Washington state, however,
found contrasting results for a sample of 302 arrested drug users
who had significantly higher accident and conviction rates than a
matched control group.  Similarly conflicting studies were found
in New York state studies of heroin addicts; one study found
heroin addicts to be three times more likely to have accidents or
convictions on their driver record, while the other study found
heroin and methadone addicts to have better driving records than
the driving population at large, both before and after entering a
methadone maintenance program.  One criticism of this letter
study, however, was that heroin addicts who elect to participate
in methadone maintenance are probably not representative of most
heroin users.  At the very least, this criticism does serve to
illustrate the point that care needs to be taken in selecting
subjects for any research project and that the results should not
be generalized beyond the identified sample population.

Our data show the accident rates for both the alcohol and drug
groups are higher than the general driving population, both for a
1974-1975 sample and for a 1991 sample.  Also, the rates for both
groups declined substantially from 1970s data to the 1991 data. 
While there have been well-documented decreases in alcohol
related accidents in the past decade, as well as a significant
reduction in the overall accident rate, these observed
differences are more likely to be reflective of changes in the
reporting or identification criteria for these groups of drivers
rather than any actual decline.

A number of recent studies have documented detrimental effects of
drugs on measures of driving skill.  Typically, the effects of
the drugs are not as severe as those of alcohol alone or alcohol
in combination with drugs.  Other studies (i.e., Moskowitz, UCLA)
show that some drugs, including cocaine, actually enhance skills
that are associated with driving.  The prevailing evidence
indicates that various drugs can affect driving performance in
various ways, both positively and negatively, although the
documented negative effects of most drugs are typically nowhere
near the magnitude of the debilitating effects of alcohol.

Given the somewhat tenuous link between drug use and driving
risk, it is questionable whether or not mandating suspension of
driving privileges for all persons convicted of drug offenses is
sensible.  California is proposing to do so in response to Public
Law 101516, requiring that all states suspend driving privileges
for six months for persons convicted of offenses involving
specified controlled substances, or risk losing federal highway
funds.  For California, the total of the highway funds lost is
$40 million for each of the next two federal fiscal years and $80
million for each year after that.

In response to this federal mandate, the governor and legislature
have three options:  to pass legislation to bring California into
compliance with the federal statute; to pass a resolution that
they did not intend to enact such a law; or the state could
forfeit hundreds of millions of dollars in future federal
funding.

We are currently conducting a study to further investigate the
relationship between drug arrests and driving risk.

The final sample that was evaluated in our study included about
330,000 subjects.  Groups consisted of felony narcotics arrestees
(arrests for opiates, cocaine, phentanol, etc.), felony marijuana
arrestees, felony arrestees for dangerous drugs, felony other-
drug arrestees, misdemeanants for possession of marijuana, and
misdemeanants for other drugs.  The statistical analysis involved
a quasi-experimental design, and we used covariances of age, sex,
and zip code (if a subject lives in an area with a high rate of
accidents, being involved in an auto accident is relevant to
one's environment).

By looking at the driving records of arrestees, we are excluding
drug users who are not arrested and who may have different
driving records.  Therefore, the records and the results may not
be reflective of all drug users.  Also, if a relationship between
drug use and driving record is found, it may not be casual,
particularly in this kind of quasi-experimental design; the
relationship may be correlational (a third factor) for which drug
use and driving accidents are symptomatic.