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.