Alcohol and Driving The Road Ahead

Transcription

1 Alcohol and Driving The Road Ahead AW Jones Department of Forensic Toxicology, University Hospital, Linköping, Sweden Background Alcohol is the world s favorite drug and the most frequently used and self-prescribed psychoactive substance in modern society (1). The problem posed by drunk drivers and the increased risk of a collision was recognized shortly after motor vehicles first appeared on the roads (2). Borkenstein and others established a quantitative relationship between a person s breath-alcohol concentration and the risk of involvement in a motor-vehicle crash (3). The results of the now seminal Grand-Rapids survey, which was first published in 1964, has been substantially verified in more recent case-controlled studies (4). Deaths on the road, many of which are alcohol-related, represent the leading cause of death in child passengers and young adults (5). Although driving under the influence of illicit drugs has attracted much recent attention from news media, policy makers and government agencies there is no escaping the fact that over-consumption of alcohol is the major contributory factor in road-traffic deaths (6). In this connection, driver fatigue, associated with sleep-deprivation, and various medical conditions can also impair a person s ability to perform skilled tasks such as driving. However, such risk factors for road-traffic safety are more difficult to control through legislation (7). My first ICADTS conference was exactly 30 years ago, namely T-1974, which was held in Toronto, Canada. Drunken driving and alcohol-related crashes were a major problem then as they are today and as they will be 30 years from now. The battle against drunk driving and the mission to prevent alcohol-related crashes has no end in sight. The fight will continue as long as people drink excessively and persist in operating a motor vehicle and also disrespect the law. This presentation gives a brief review and opinion about the current situation regarding alcohol and traffic safety and what might be done to deter the perpetual hard-core drinking driver. Threshold limits of alcohol concentration The vast majority of countries around the world enforce per se alcohol concentration limits for driving, thus making it a lot easier to prosecute offenders (table 1). This kind of legislation puts major emphasis on the concentration of alcohol measured in a specimen of blood, breath or urine (8). The evidence required for a successful prosecution no longer hinges on proof that the driver was under the influence of alcohol and unfit to operate the vehicle safely. The alcohol per se statutes create a razor-sharp difference in penalty for those just above or just below the legal limit for driving. This legal framework necessitates a careful control and scrutiny of the analytical methods used for legal purposes. The threshold alcohol limit for driving in UK has remained unchanged since the Road- Safety Act of 1967, being 80 mg/100 ml blood, 107 mg/100 ml urine or 35 µg/100 ml breath. Most other EU countries have, in the meantime, lowered their per se blood-alcohol limit to 50 mg/100 ml and Sweden and Norway currently enforce a limit of 20 mg/100 ml. Setting these punishable alcohol concentration limits depends more on political forces and

2 public opinion rather than scientific investigations and traffic-safety research. In reality, experience has shown that lowering the threshold alcohol limits for driving does not deter the hard-core drinking driver and other measures are therefore urgently needed. Table 1. Comparison of threshold blood- and breath-alcohol concentration limits for driving in various countries. The units of concentration are those used in UK and Ireland, namely mg/100 ml or µg/100 ml. Country Blood-alcohol limit Breath alcohol limit Sweden 20 mg/100 ml 1 10 µg/100 ml Norway 20 mg/100 ml 1 10 µg/100 ml Finland 50 mg/100 ml 1 22 µg/100 ml Denmark 50 mg/100 ml 1 25 µg/100 ml UK 80 mg/100 ml 35 µg/100 ml Ireland 80 mg/100 ml 35 µg/100 ml Netherlands 50 mg/100 ml 22 µg/100 ml Most EU countries 50 mg/100 ml 25 µg/100 ml USA 80 or 100 mg/100 ml 28 or 47 µg/ 100 ml Canada 80 mg/100 ml 38 µg/100 ml Australia 50 mg/100 ml 24 µg/100 ml 1 In reality mg/100 g blood. In many US states, the threshold alcohol limit for driving is set at 20 mg/100 ml for people under 21-years of age. This strategy has seemingly helped to reduce fatalities on the roads among younger drivers. It seems that novice drinkers and novice drivers represent a particularly dangerous combination enhancing the risk for involvement in alcohol-related crashes. US federal law mandates a lower blood-alcohol limit (40 mg/100 ml) for those who operate commercial vehicles (buses, trains etc.) as well as others involved with safety-sensitive transportation work. Other countries should follow this lead and even consider zero-tolerance limits for people responsibly for public transportation. Alcohol and drugs in traffic fatalities A recent survey from Sweden looked at the occurrence of alcohol along with both illicit and prescription drugs in drivers killed on the roads during 2000, 2001 and The results of this survey are summarised in table 2. Table 2. Summary of analytical findings in blood from drivers killed in traffic crashes in Sweden over a 3-year period (n = number of cases). Findings 2000 (N = 293) 2001 (N = 283) 2003 (N = 279) Alcohol only 52 (18%) 55 (19%) 41 (15%) Alcohol + other drugs 1 6 (2%) 16 (5%) 20 (6%) Illicit drugs 14 (5%) 19 (7%) 21 (7%) Licit drugs 2 41 (14%) 40 (14%) 29 (10%) Total 114 (39%) 130 (46%) 111 (40%) 1 Both licit and illicit with a mean blood-ethanol 170 mg/100 ml, 2 Not necessarily psychoactive substances. The above results highlight the clear and consistent dominance of alcohol involvement in road-traffic deaths and especially those people with high blood-alcohol concentration (mean 170 mg/100 ml). Although the problem caused by drug-impaired drivers should not be under-estimated because information from several sources shows that this kind of deviant behaviour is on the rise (6). Nevertheless, countermeasures against drunk driving deserve major emphasis from government transport and safety agencies and other action groups.

3 Measuring alcohol in body fluids Technology for measuring alcohol in body fluids (blood, breath, urine, saliva and sweat) has advanced considerably and non-intrusive methods that yield on-the-spot results are preferred (e.g. breath-alcohol analysis). However, a person cannot be forced to provide a specimen of breath and in some jurisdictions refusal to co-operate with police procedures is a common occurrence and seemingly increasing. Statistics have shown that about 20% of positive roadside breath-alcohol tests in Sweden are below the legal limit for driving when the evidential breath-alcohol test (EBT) is made at a police station about 1-1½ h later (table 3). This high proportion of people not being prosecuted is troublesome and can be reduced appreciably if the EBT is made directly at the roadside. Eliminating the need to transport the suspect to a police station also results in a saving of police time and manpower. Besides enhancing conviction rate the need to back-extrapolate a person s blood- or breath-alcohol concentration to the time of driving, which is still required in some jurisdictions, is eliminated. Table 3. Percent of positive roadside breath-alcohol tests that were below the legal alcohol limit for driving by the time an evidential blood or breath-test was made (data from Sweden. Year N 1 Breath test below limit (%) Blood tests below limit (%) Total tests below limit (%) (24) 1205 (21) 4942 (24) (23) 1001 (20) 5018 (23) (23) 847 (18) 4440 (21) (21) 757 (17) 3827 (20) (20) 669 (16) 3426 (19) (20) 974 (21) 2937 (19) (19) 791 (17) 3567 (23) (19) 798 (17) 2809 (18) (20) 644 (13) 2939 (18) 1 Total number of blood and breath-alcohol tests in Sweden. Evidential breath-testing at the roadside In several US States (e.g California) legislation exists that allow conducting the evidential breath test at the roadside in close proximity with driving. And also in Sweden police authorities are keen to reduce the time between driving and the evidential breath test. For this purpose a new and more robust breath-alcohol analyzer has been developed (Evidenzer), which can be used at a police station (stationary) or in a police vehicle (mobile). The following breath-alcohol devices are also capable of being used mobile and thus allowing evidential roadside tests of drivers. Alcotest EPAS Intoxilyzer 8000 Alco-Sensor IV-XL Evidenzer Preliminary breath-alcohol screening tests (PBTs) are still necessary for orientation purposes and to differentiate individuals who might be driving under the influence of drugs other than alcohol. A positive PBT is followed by an evidential breath-test (EBT) after a min observation period. This time delay is necessary to avoid later challenges that the breath sample analysed was contaminated with mouth alcohol. Many EBTs are fitted with slope detectors to detect mouth-alcohol by monitoring the shape (waviness and rise) of the person s breath-alcohol exhalation profile. On-going studies aimed at investigating whether the min observation/deprivation can be shortened show promise thanks to new and more sophisticated algorithms.

4 By moving the EBT about 1-2 hour closer to the time driving will obviously attract publicity and media attention and if this is coupled with more intense police controls of driving this could act as an added a deterrent, at least in the short term. Also the prosecution of drunk drivers with immediate sanctions and on-the-spot revocation of the license becomes more streamlined. Studies have shown that drunk drivers eliminate alcohol from blood at a rate of 19 mg/100 ml per hour on average and on top of this a deduction is currently made form the EBT result to allow for uncertainty in the measurements. This explains in large part the 20% false-positive PBT results. Frivolous defence arguments Defending drunk drivers is big business in some countries especially in USA. Many law firms specialize in defending the drinking driver and a vast literature exists with annual conferences and seminars being held to educate lawyers about developments in the science and technology of alcohol testing and the pros and cons of new defence challenges. Experience has shown that the vast majority of such defence arguments are bogus and lack merit. One of the most successful defence arguments is alleged consumption of alcohol after driving. If the drunk driver is not apprehended at the wheel this defence tactic, which has become known as the hip-flask or the glove-compartment defence, will surely arise. This argument is not easy for the prosecution to disprove and many acquittals have been documented. The various reasons given for consumption of alcohol after a traffic-crash include the need to calm the nerves and reduce stress and anxiety. The hip-flask ploy is common among hit-and-run drivers if and when the police eventually apprehend them. In one German study 33% of driver s admitted to the charge of drunk driving at the time of the offence but later, when the case went to court, they claimed they had consumed alcohol after driving. In another 33% of cases the amounts consumed after driving gradually increased as the time of the court appearance drew closer. Although the concentration of alcohol in blood, breath or urine is accepted as evidence for prosecution, the courts also consider evidence to the contrary. Surprisingly, such evidence might entail what the suspect admits to have consumed before driving, which is hardly compelling. It must be obvious that people suspected of drunk driving cannot be expected to be frank about their drinking practices. To deal with the multitude of defence arguments, specialist DUI/DWI prosecutors might be trained to handle such cases. The training of police officers could also be improved to ensure they gather the best possible evidence without loopholes so that charges are dropped or reduced at trial. Judges should consider appointing court experts if and when intricate medical, scientific or technical issues are crucial for the outcome of the case. The current practice of expert witnesses being called by the opposing parties tends to confuse the jury when two well-qualified individuals expound quite different opinions. The presiding magistrate or judge should not allow into evidence frivolous and unfounded challenges that lack substance. What a suspect admits about alcohol consumption is not exactly rock-solid evidence and there is usually not one shred off objective verifiable information to support such statements. What can be done about recidivism? Recidivism is high among convicted drunk drivers (~30% in some studies) and many continue to drive even without a valid license. Research is needed to develop better ways to deal with binge drinkers and hard-core drinking drivers. The use of electronic tagging

5 with an ankle bracelet and monitoring alcohol intake overtime with a sweat patch is one new innovation. Stricter supervision during probation and more random alcohol testing has also had some success. However, if drunken people cannot be prevented from starting and operating a motor vehicle then it seems futile to keep them off the road. One sanction that holds merit is mandatory use of ignition interlock systems activated by a person s breath-alcohol concentration (9). The increasing use of such devices needs to be encouraged especially for repeat offenders regardless of the number of vehicles they own. Such interlock devices might also be considered for first-time offenders having high BAC or BrAC when arrested. The Swedish government recently proposed that in the future all new cars should be fitted with ignition interlock devices, although the feasibility of this idea remains to be evaluated. Ignition interlock systems are being made available by more and more manufactures and the increased competition will result in lower costs for this technology. Some remaining problems such as positive identification of the owner can be solved by digital imaging technology or by recognizing a specific breathing pattern or as today with one or more rolling retest being required. Long delays before a vehicle starts under cold winter conditions can be resolved by incorporating a separate heating element in the device. The costs for fitting interlock devices might be included in the sentence given to drunk drivers or via increased vehicle insurance costs. All this seems a small price to pay if it helps to prevent recidivism. Any failed attempts to start the vehicle need to be documented and alcohol concentrations evaluated periodically. Laws exist in some countries to impound or confiscate the vehicle of repeat offenders but the effectiveness of this sanction has not been properly evaluated. Some jurisdictions have started to use graded penalties for drunk driving and more severe fines when the concentration of alcohol in blood or breath is unusually high, so-called tired sanctions. Concluding remarks It is common knowledge that many apprehended drunk drivers have problems with their drinking and could be diagnosed medically as being alcohol dependent. The argument might be made that such people are in need of treatment for their alcoholism as opposed to traditional punishment and fines for drunk driving. Accordingly, much interest has focused on the use of biochemical tests as well as questionnaires aimed at identifying problem drinkers and alcoholics among convicted drunk drivers. Repeat offender with high blood-alcohol concentration when apprehended (>150 mg/100 ml) are in need of education and rehabilitation during the period of detention. Biological markers can be used to detect problem drinkers and allow medical intervention. This is especially important before a person gets re-licensed after a DUI conviction. Repeat offenders need to prove to the authorities that they are no longer dependent on alcohol. Among the most widely used biochemical markers for excessive alcohol consumption (> g per day) are the serum enzymes (GGT, AST, ALT), mean corpuscular volume of red cells (MCV) and especially carbohydrate-deficient transferrin (CDT). An urgent need exists for more public debate and education about the dangers of overconsumption of alcohol and the risk for damaging health and causing premature death. Guidelines for sensible drinking should be re-vamped with more publicity and targeted at younger age groups, who might just be learning to drive. Other countermeasures for newly licensed drivers that merit attention include conditional or restricted driving permits,

6 zero-alcohol tolerance laws, lower speed-limits, night-time curfews and a restriction on carrying passengers. Unfortunately such measures have negligible influence on the hard-core drinking driver and the binge drinker, who mostly represent criminal elements in society. Making repeat offenders conspicuous in the traffic by tagging their vehicles in some way requires further study. Many drunk drivers (30%) lack a valid driving permit or might never have owned one. Promoting the use of random testing of motorists and escalating police checkpoints with blitz controls of motorists, as done in some Australian states, will enhance discovery of unlicensed drivers. The notion of a smart-card or electronic chip incorporated into a person s driving license and being necessary to start the engine seemed to hold great promise but has not been widely accepted. Stopping people from re-offending should be paramount and measures to confiscate or impound the vehicle are encouraged and compulsory fitting of ignition interlock systems seems the only way to go. Un-licensed drivers are often also un-insured drivers, which compounds the problem for those injured or killed by drinking drivers. In conclusion, it seems that the road ahead for alcohol and driving is far from straight and there will be many bends, U-turns and some cul-de-sacs. Alcohol is a legal drug and overconsumption of alcohol and drunkenness are facts of life in towns and cities throughout the world. As long as people, alcohol and motor vehicles exist there will always be drunk drivers. Better Information and education packages that pack a punch and contain plain language about the hazards of drinking and driving are needed. Lower taxes on alcoholic beverages, as one consequence of EU membership, will boost total alcohol consumption in society and inevitably lead to escalation in drunk driving and deaths on the roads. References 1. Gibbons B. Alcohol the legal drug. National geographic 181:3-35, Editorial. The Quarterly Journal of Inebriety 26;308, Borkenstein RF. The role of the drinking driver in traffic accidents (The Grand Rapids Study). Blutalkohol 11; supplement 1, 1974, pp (first published 1964). 4. Compton RP, Blomberg RD, Moskowitz H, Burns M, Peck RC, Florentino D. Crash risk of impaired driving. In proceedings of the 16 th international conference on alcohol drugs and traffic safety, Montreal, Shults RA. Child passenger deaths involving drinking drivers in United States JAMA 291;934, Jones RK, Shinar D, Walsh JM. State of knowledge of drug-impaired driving. National Highway Traffic Safety Administration (NHTSA), DOT HS Stewart K., Alcohol Involvement in Fatal Crashes: Comparisons Among Countries, US Department of Transportation, National Highway Traffic Safety Administration, DOT HS , Jones AW. Enforcement of drink-driving laws by use of "per se" legal alcohol limits: Blood and/or breath concentration as evidence of impairment. Alcohol, Drugs & Driving 4;99-112, Marques PR, Tippetts AS, Voas RB. The alcohol interlock: an underutilized resource for predicting and controlling drunk drivers. Traffic Inj Prev. 4:188-94, 2003.