The major problem in enforcing the zero BAC limit is ensuring that the province or territory enacts accompanying legislation authorizing the police to demand a breath sample from drivers subject to this limit. There has been no problem with drivers testing positive with exceedingly small amounts of alcohol in their breath samples, because of natural processes or diet. Presumably, the machines have thresholds to eliminate this problem.

Conflict of Interest:

None declared

How easy is it to enforce zero limit in the face of possiblity of physicigical sources of alcohol and uses of other dietry and household sources of alcohol? There might be a lot or few false positive cases as a result. Is there anything of in the scientific evidence base?

Conflict of Interest:

None declared

Dear Editor,

We are grateful for the letter of Desapriya et al. regarding our recent Special Feature, and agree with the sentiments it expresses. We, too, view our proposal to extend BAC limits to the age of 21 as part of a much larger initiative to reduce traffic crashes among youth. Indeed, we outlined a more comprehensive approach to the issue in our 2006 report, Youth and Impaired Driving in Canada: Opportunities for Progress, which was published by MADD Canada and Allstate Insurance. The report includes proposals not only for graduated licensing and extended BAC restrictions, but also for more effective police enforcement powers and the regulation of alcohol sales. The full report can be downloaded at www.madd.ca.

Regards,

Erika Chamberlain and Robert Solomon

Dear Editor

It is timely that Chamberlain and Solomon [1] are proposing an extended zero blood alcohol limit for young drivers and it will definitely save more young lives; however, we believe that drinking and driving is an important part of this complex problem and we have to streamline all other Graduated Driver Licensing (GDL) components in order to realize the significant impact of GDL in saving our children in the future.

For more than a century alcohol has been recognized as one of the principal risk factors for motor vehicle crashes.[2] Alcohol-related motor vehicle crashes represent a leading cause of morbidity and mortality, particularly in young people, carrying an immeasurable human cost, as well as an enormous burden to society. Eighty-one percent of Canadians have rated drinking and driving as one of the most significant social issues they must face today, placing it ahead of other prominent issues, including health care, pollution, and the state of the economy.[3]

Young drivers continue to be a major traffic safety concern. Several factors contribute to the increased risk of traffic crash-related fatalities among adolescents and young adults including less experience driving, higher rates of drinking and driving, excessive speeding and lower rates of seat belt use. Given the significance of alcohol impaired driving to youth mortality, a key issue is to enhance the effectiveness of prevention policy and programming. Mothers Against Drunk Driving Canada has recommended that the zero BAC limits for young drivers be extended to the age of 21.[1]

Previous studies in other countries have also shown that an increased BAC limit is a difficult transition for young drivers (after GDL from a zero tolerance of alcohol to a dangerously higher BAC limit) and it was a major factor which contributed to their increased crash involvement in Australia. [4] Another recent study showed that new drivers experienced a difficult transition from the zero tolerance policy to the adult driver BAC limit (0.08 percent).This has been compromising overall traffic safety in New Zealand. [5]

In addition, New South Wales introduced extended zero tolerance laws to their new drivers.[6] Young drivers are inexperienced not only in driving but also in drinking and when they combine the two activities, this could be deadly. It is not surprising given that the risks of a fatal crash while driving at the current Canadian legal BAC limit (and in many other motorized countries including New Zealand, UK, USA) are alarmingly high even for experienced mature drivers.

The legal BAC limit in most motorized countries is too high; people often mistakenly believe that they may drive up to a BAC of 0.08 percent, overlooking the fact that driving is still impaired at lower concentrations. To set a blood alcohol limit so high that a 72 kg man can drink four bottles of beer and still be under the legal limit has consequences for drunk drivers, passengers of the vehicle and all other innocent vulnerable road users. Importantly, it may adversely influence a person’s estimates of their relative risk of injury or death while driving. Therefore drinking and driving legislation policies and decisions about enforcement need to be hinged on the scientific evidence. [2]

As Rivara and colleagues (2001) [7] pointed out, one of the most effective enabling factors for injury control is legislation. Importantly, laws must be capable of communicating the public health and traffic safety hazards of drinking and driving. As veteran pediatric injury prevention experts like Simons-Morton and Winston (2006) [8] have shown, laws have the power to change drivers’ perceptions of the value of safety practices.

However, we must understand that the youth traffic crash problem is interwoven with several other factors. [9] Therefore, it is important to have an overall approach that is built on the foundation of GDL laws to prevent young driver crashes. We should push for more comprehensive legislation and better enforcement based on the currently available best evidence.

To achieve the Canadian national road safety strategy target 2010, various road safety strategies for new drivers must receive priority. [10] It is evident that our current GDL laws have been steering young drivers in the right direction. However, in addition to extended zero BAC limits, until a complete cell phone ban, maximum speed limits, and compulsory seat belt laws are incorporated into the graduated licensing system throughout Canada, it is unlikely that the national road safety strategy target for 2010 will be achieved. One of the major reasons teens are killed or seriously injured when involved in traffic crashes is lack of seat belt use. It is well known that when drivers drink and drive, they tend to lack seat belt use. If we have effective policies that separate drinking and driving we could reduce non-belted youth drivers in our communities. In addition, GDL laws that explicitly include requirements for seat belt use in all phases, and sanctions that prohibit “graduation” to the next licensing phase if there is a seat belt citation, could increase teen seat belt use substantially. A zero-tolerance program for nonuse of safety belts, use of cell phone while driving and exceeding safe posted speed limits could be implemented, with immediate loss of license or other administrative penalties resulting for non-compliance. One major step we need to take irrespective of anything urgently is that we need to promote responsible driving among our children.

No policy can be effective unless it is adequately implemented and enforced, and there is awareness of both the policy and the enforcement efforts on the part of the intended targets. As with all above zero-tolerance programs, enforcement and strategic media campaigns to increase youth’s awareness of the law and of its enforcement efforts could significantly increase the effectiveness of these laws.

References

[1]. Chamberlain E, Solomon R. Zero blood alcohol concentration limits for drivers under 21: lessons from Canada. Inj Prev. 2008; 14(2):123-128.

[2].Desapriya EB. Alcohol limit for drink driving should be much lower. BMJ 2004; 328(7444):855-6.

[3]. Beirness, D.J., Simpson, H.M., Mayhew, D.R., et al; The Road Safety Monitor 2005- Drinking and Driving- Traffic Injury Research Foundation 2005

[4]. Senserrick TM. Graduation from a zero to .05 BAC restriction in an Australian graduated licensing system: a difficult transition for young drivers? Annu Proc Assoc Adv Automot Med. 2003;47:215-31.

[5]. Senserrick, T., Harworth, N., Review of literature regarding National International young driver training licensing and regulatory systems. Melbourne: Monash University Accident Research Centre, 2005.

[6]. Keall M.D., Frith W.J., Patterson T.L. The influence of alcohol, age and number of passengers on the night-time risk of driver fatal injury in New Zealand. Accid Anal Prev. 2004;36(1):49-61.

[7]. Rivara FP, Bennett E, Crispin B, Kruger K, Ebel E, Sarewitz A. Booster seats for child passengers: lessons learned for increasing their use. Inj Prev. 2001;7(3):210-3.

[8]. Simons-Morton BG, Winston FK. Translational research in child and adolescent transportation safety. Eval Health Prof. 2006;29:33 DOI: 10.1177/0163278705284442.

[9].Desapriya E, Joshi P, Pike I. Effects of graduated driver licensing on fatalities in 16-year-olds. Pediatrics 2006;118(5):2252-3.

[10]. Canada’s Road Safety Targets to 2010 http://www.tc.gc.ca/roadsafety/tp/tp13736/pdf/CRS_Target.pdf (accessed 15th March 2008)