1 USA Today. "Growing danger: Drugged driving." October 21, 2004; Las Vegas Review-Journal. "Congress must address issue of drugged driving." March 21, 2004; New York Times. "Many, undetected, use drugs and then drive." November 14, 2002.

2 To date, only Pennsylvania, Nevada and Virginia have enacted per se standards for DUID offenses. Under Pennsylvania's law, motorists with detectable levels of THC in the blood above 5 ng/ml are guilty of DUID. Under Nevada's law, motorists with detectable levels of THC in the blood above 2 ng/ml or detectable levels of THC-COOH in the urine above 15 ng/ml are guilty of DUID. Virginia's law exempts marijuana and marijuana metabolites.

3 US Department of Transportation, National Highway Traffic Safety Administration. State of Knowledge of Drug-Impaired Driving: FINAL REPORT. September 2003.

4 Skopp et al. as cited by Grotenhermen and Leson. Testing for Impairment by Cannabis: A review of established and emerging approaches and methods. May 2004.

5 Persistence of urinary marijuana metabolites after a single dose of THC may produce detectable metabolites in urine for up to 12 days. See specifically: Law et al. Forensic aspects of the metabolism and excretion of cannabinoids following oral ingestion of cannabis resin. J Pharm Pharmacol. 1984: 289-94. Persistence of urinary marijuana metabolites after supervised abstinence in heavy, longtime users has been recorded in clinical studies for periods of 30 to 70 days. See specifically: Ellis et al. Excretion patterns of cannabinoid metabolites after last use in a group of chronic users. Clin Pharmacolo Ther. November 1985: 572-578 and Dackis et al. Persistence of urinary marijuana levels after supervised abstinence. Am J Psychiatry. September 1982: 1196-1198.

6 Arizona's law calls for mandatory imprisonment upon conviction for a first offense.

7 Georgia's law calls for mandatory imprisonment upon conviction for a first offense.

8 Iowa's law calls for mandatory imprisonment upon conviction for a first offense.

9 Michigan's law took effect in October 2003.

10 Minnesota's law exempts marijuana and marijuana metabolites, stating, "It is a crime for any person to drive, operate, or be in physical control of any motor vehicle ... when the person's body contains any amount of a controlled substance in schedule I or II other than marijuana or tetrahydrocannabinols."

12 Utah's law calls for mandatory imprisonment upon conviction for a first offense.

13 Wisconsin's law took effect in January 2004.

15 As an analogy, think of a drug metabolite as similar to a fingerprint. Though it indicates a person was present at a certain place, it does not give specific information as to when the person was present, or why.

16 US Department of Justice, Bureau of Justice Statistics. Drugs, Crime, and the Justice System (NCJ-133652). December 1992.

17 US Department of Transportation, National Highway Traffic Safety Administration. State of Knowledge of Drug-Impaired Driving: FINAL REPORT.

18 Yale Caplan. "Technology for Testing Drugs of Abuse in DUID." In: Developing Global Strategies for Identifying, Prosecuting, and Treating Drug-Impaired Drivers: Symposium Report. June 2004.

19 See footnote 16.

20 US Department of Transportation, National Highway Traffic Safety Administration. State of Knowledge of Drug-Impaired Driving: FINAL REPORT.

21 Ibid. Figure 3-1: Drug Detection Periods In Various Specimens; See also: Huestis et al. Relationship of (9)-tetrahydrocannabinol concentrations in oral fluid and plasma after controlled administration of smoked cannabis. J Anal Toxicol. September 2004: 394-399.

22 See footnote 4.

23 US Department of Transportation, National Highway Traffic Safety Administration. State of Knowledge of Drug-Impaired Driving: FINAL REPORT.

24 Drummer et al. The involvement of drugs in drivers killed in Australian road traffic crashes. Accid Anal Prev. 2004: 239-248

25 Huestis et al. Blood cannabinoids: Absorption of THC and formation of 11-OH-THC and THC-COOH during and after smoking marijuana. J Anal Toxicol. 1992: 276-282; See also: Papafotiou et al. An evaluation of the sensitivity of the Standardised Field Sobriety Tests (SFSTs) to detect impairment due to marijuana intoxication (Figure 1: Level of THC in plasma after smoking placebo, low- and high-dose cannabis cigarettes.) Psychopharmacology. 2004 [Epub ahead of print]

26 Grotenhermen et al. Developing per se laws for driving under the influence of cannabis (DUIC). Paper presented at the 17th International Conference on Alcohol, Drugs and Traffic Safety. August 10, 2004.

27 US Department of Transportation, National Highway Traffic Safety Administration. State of Knowledge of Drug-Impaired Driving: FINAL REPORT. Figure 3-1: Drug Detection Periods In Various Specimens; See also: Dolan et al. An overview of the use of hair, sweat and saliva to detect drug use. Drug Alcohol Rev. 2004: 213-217 and Verstraete. Detection times of drugs of abuse in blood, urine and oral fluid. Ther Drug Monit. 2004: 200-205.

28 US Department of Transportation, National Highway Traffic Safety Administration. State of Knowledge of Drug-Impaired Driving: FINAL REPORT.

29 Spiehler et al. Analysis of Drugs in Saliva. In Goldberger et al: On-Site Drug Testing. Humana Press Inc. 2001.

30 Niedbala et al. Detection of marijuana use by oral fluid and urine analysis following single-dose administration of smoked and oral marijuana. J Anal Toxicol. 2001: 289-303.

31 TISPOL Press Release: Participation in Operational Testing of Drug Detection Devices by Manufacturers of Fluid Screening Devices.

32 Herald Sun. Roadside drug tests in turmoil. December 22, 2004.

33 Grotenhermen and Leson. Testing for Impairment by Cannabis: A review of established and emerging approaches and methods. May 2004.

34 Grotenhermen et al. Developing Science-Based Per Se Limits for Driving Under the Influence of Cannabis: Findings and Recommendations by an Expert Panel. (FORTHCOMING)

35 Developing Global Strategies for Identifying, Prosecuting, and Treating Drug-Impaired Drivers: Symposium Report. June 2004.

36 Reviews include: David Hadorn. A review of cannabis and driving skills. In: Guy et al (Eds) The Medicinal Uses of Cannabis and Cannabinoids. London: Pharmaceutical Press. 2004: See specifically, "In conclusion, driving ability does not appear to be substantially impaired by cannabis." See also: Canadian Special Senate Committee on Illegal Drugs. Cannabis: Our Position for a Canadian Public Policy. 2002: See specifically Chapter 5: "Driving Under the Influence of Cannabis;"  UK Department of Environment, Transport and the Regions (Road Safety Division). Cannabis and Driving: A Review of the Literature and Commentary. 2000;  Allison Smiley. Marijuana: On-Road and Driving Simulator Studies. In: H. Kalant et al. (Eds) The Health Effects of Cannabis. Toronto: Center for Addiction and Mental Health. 1999: 173-191.

37 Sexton et al. The influence of cannabis on driving: A report prepared for the UK Department of the Environment, Transport and the Regions (Road Safety Division). 2000; UK Department of Environment, Transport and the Regions (Road Safety Division). Cannabis and Driving: A Review of the Literature and Commentary;  2000; Allison Smiley. Marijuana: On-Road and Driving Simulator Studies.

38 These findings are somewhat limited because only 4 percent of the drivers studied tested positive for THC in their blood. US Department of Transportation, National Highway Traffic Safety Administration. The Incidence and Role of Drugs in Fatally Injured Drivers: FINAL REPORT. October 1992.

39 Hindrick Robbe. Marijuana's effects on actual driving performance. Institute for Human Psychopharmacology, University of Maastricht. 1993.

40 Chesher et al. Cannabis and alcohol in motor vehicle accidents. In: Grotenhermen and Russo (Eds) Cannabis and Cannabinoids: Pharmacology, Toxicology, and Therapeutic Potential. New York: Haworth Press. 2002: 313-323.

41 Ramaekers et al. Dose related risk of motor vehicle crashes after cannabis use. Drug and Alcohol Dependence. 2004: 109-119.

42 These findings are somewhat limited because only 3 percent of the drug-positive drivers found to be responsible for their crash tested positive for THC in their blood. By comparison, 58 percent tested positive for alcohol. Drummer et al. The involvement of drugs in drivers killed in Australian road traffic crashes. (Also note: Hadorn and others warn that findings from retrospective studies must be interpreted with caution because of the "absence of an appropriate control group. Ideally, control blood samples would be obtained from 'random' drivers passing by the same locations at approximately the same time as the drivers involved in the collisions. However, for obvious logistical and ethical reasons this is never done. [Therefore,] ... studies relying on blood tests for cannabis cannot meaningfully assess the effects of cannabis on risk of collision 'given the absence of valid baseline data for cannabis detected in the non-involved population.'")

43 Grotenhermen et al. Developing Science-Based Per Se Limits for Driving Under the Influence of Cannabis: Findings and Recommendations by an Expert Panel.

44 Ibid; See also Allison Smiley. Marijuana: On-Road and Driving Simulator Studies

45 Ibid; See also United Kingdom's Advisory Council on the Misuse of Drugs.  The Classification of Cannabis Under the Misuse of Drugs Act of 1971. 2002: See specifically: Chapter 4, Section 4.3.5: "Cannabis differs from alcohol; ... it seems not to increase risk-taking behavior. This may explain why it appears to play a smaller role than alcohol in road traffic accidents."

46 http://www.walshgroup.org

47 http://www.bensingerdupont.com

48 These guidelines subject licensed commercial drivers to submit to random urinalysis for the purpose of screening for illicit drug metabolites. These regulations also establish per se guidelines for drug metabolites, although these cutoff levels are admittedly not correlated to impairment.

49 Robert Dupont. "Drugs and driving." Letter to the editor: USA Today. October 28, 2004.

50 Robert Dupont. "Conviction is an Opportunity for Intervention." In: Developing Global Strategies for Identifying, Prosecuting, and Treating Drug-Impaired Drivers: Symposium Report. June 2004.

51 Ibid.

52 Grotenhermen et al. Developing Science-Based Per Se Limits for Driving Under the Influence of Cannabis: Findings and Recommendations by an Expert Panel.

53 US Department of Transportation, National Highway Traffic Safety Administration. State of Knowledge of Drug-Impaired Driving: FINAL REPORT.

54 Ibid.