Driving Under the Influence

I got arrested for DUI Marijuana DUI-C (DUI-THC, DUI-MJ).  The police say I failed the voluntary roadside maneuvers and they took a blood test showing 5+ nanograms of THC, should I get a lawyer?

Well, yes.  Almost no one passes voluntary roadside maneuvers or standardized field sobriety tests or the drug recognition examination.  The 5 ng limit is not based on science.  It is just designed to make prosecutions easier.  It tends to shift the burden of proof to the defense.  But the science supports us.

Remember, you do not have to agree to the voluntary roadside maneuvers.  You do not have to speak with police.  You do not have to allow the police to search your belongings or car.  The police may still search, but you do not have to consent.  Just say your lawyer said never consent.

The Facts

The following is science and not law.  The science is the same regardless of whether you are charged with DUI Marijuana (DUI-C, DUI-THC, DUI-MJ) in Boulder Colorado or Broomfield or Denver.

There is no consensus regarding what THC/blood standards are appropriate predictors of psychomotor impairment

  • “In terms of attempting to link drug concentrations to behavioral impairment, blood is probably the specimen of choice. However, forensic toxicologists generally have failed to agree on specific plasma concentrations that could be designated as evidence of impairment.” (NHTSA. 2003. op. cit.)
  • "One of the program's objectives was to determine whether it is possible to predict driving impairment by plasma concentrations of THC and/or its metabolite, THC-COOH, in single samples. The answer is very clear: it is not. (Robbe, 1993. op. cit.)
  • “[T]here is no direct correlation between driving impairment and THC concentration.” (Hartman and Huestis. 2013. Cannabis effects on driving skills)
  • “It is difficult to establish a relationship between a person's THC blood or plasma concentration and performance impairing effects. … It is inadvisable to try and predict effects based on blood THC concentrations alone, and currently impossible to predict specific effects based on THC-COOH concentrations. (NHTSA website)
  • Individual drivers can vary widely in their sensitivity for THC induced impairment as evinced by the weak correlations between THC in serum and magnitude of performance impairment.” (Ramaekers et al., 2009. Dose related risk of motor vehicle crashes after cannabis use: an update. In: Drugs, Driving, and Traffic Safety. World Health Organization)
  • “It should be stressed however that the predictive validity of any per se limit is confined to the driving population at large, and not necessarily applicable to each and every driver as an individual.”  (Ramaekers et al., 2009. op. cit.)
  • Plasma of drivers showing substantial impairment in these studies contained both high and low THC concentrations; and drivers with high plasma concentrations showed substantial, but also no impairment, and even some improvement." (Robbe, 1993. op. cit.)

There is a wide variance of THC’s effects among individual consumers

  • Individual drivers can vary widely in their sensitivity for THC induced impairment as evinced by the weak correlations between THC in serum and magnitude of performance impairment.” (Ramaekers et al., 2009. Dose related risk of motor vehicle crashes after cannabis use: an update. In: Drugs, Driving, and Traffic Safety. World Health Organization)
  • “It should be stressed however that the predictive validity of any per se limit is confined to the driving population at large, and not necessarily applicable to each and every driver as an individual.”  (Ramaekers et al., 2009. op. cit.)
  • Plasma of drivers showing substantial impairment in these studies contained both high and low THC concentrations; and drivers with high plasma concentrations showed substantial, but also no impairment, and even some improvement." (Robbe, 1993. op. cit.)

Cannabis consumption impacts the psychomotor performance of naïve and experienced subjects differently

  • “THC did not affect performance of heavy cannabis users in the critical tracking task, the stop-signal task, and the Tower of London. These tasks have previously been shown to be very sensitive to the impairing potential of THC when administered to infrequent cannabis (users). The lack of THC on these tasks basically confirms the previous notions that heavy cannabis users can develop tolerance to behaviorally impairing effects of THC.” (Ramaekers et al., 2010. op. cit.)
  • Experienced smokers who drive on a set course show almost no functional impairment under the influence of marijuana.” (Sewell et al., op. cit.)

Residual levels of THC may be present in the blood of chronic consumers for several days without evidence of new use or any associated impairments of psychomotor performance, thus confounding proper interpretation

  • “On day 7, 6 full days after entering the unit, six participants (out of 25) still displayed detectable THC concentrations. … The highest observed THC concentrations on admission (day 1) and day 7 were 7.0 and 3.0 ng/ml, respectively. … Conclusions: Substantial whole blood THC concentrations persist multiple days after drug discontinuation in heavy chronic cannabis users. … These findings also may impact on the implementation of per se limits in driving under the influence of drugs legislation.” (Karschner et al., 2009. Do Delta- 9-tetrahydrocannabinol concentrations indicate recent use in chronic cannabis users?)
  • “A threshold of 2-3ng/ml THC as an indicator of recent drug use (i.e, smoking within the previous 6 hours) as recommended by Huestis et al appears to be valid only for occasional users. Heavy users might exhibit measurable cannabinoid concentrations in blood (median: 3.2ng/ml THC in blood serum), even if the last cannabis use was more than 24 hours ago. … Therefore, cannabinoid concentrations in heavy users’ blood from a later elimination phase might not be distinguished from an acute use of an occasional user.” (Toennes et al., 2008. Comparison of cannabinoid pharmacokinetic properties in occasional and heavy users smoking a marijuana or placebo joint)
  • [D]etection of psychoactive cannabinoids seem possible over a time period of more than 24-48 hours after abstaining from cannabis smoking. … Impairment could not be assessed … in any subject at the time of blood sampling.” (Skopp et al., 2008. Cannabinoid concentrations in spot serum samples 24-48 hours after discontinuation of cannabis smoking.)

Contact a Colorado criminal defense lawyer representing clients in Gunbarrel, CO today to schedule your initial consultation.

No practical way for LEOs to collect a blood sample in a time-sensitive manner

  • “[I]n DUID cases, the delay between the accident and the final blood draw can be long and back-extrapolation is not an option due to the complex pharmacokinetic profile of THC.” (Wille et al., 2010. Conventional and alternative matrices for driving under the influence of cannabis.)
  • “What 5 ng/mL means in terms of actual impairment is hard to calculate, as THC levels in the blood peak quickly following inhalation then decrease rapidly according to complex pharmacokinetics, making it almost impossible to extrapolate backwards from the concentration of THC at the time of the blood test to the concentration at the time of the traffic accident.” (Sewell et al. op cit)

Changes in performance are typically short-lived

  • 70 percent of subjects manifest ‘significant’ psychomotor impairment 20-40 minutes following cannabis inhalation; this percentage falls to 30 percent after 60 minutes (Berghaus et al., 1998 as cited by Gieringer)
  • Peak acute effects following cannabis inhalation are typically obtained within 10 to 30 minutes (NHTSA. 2004. Drugs and Human Performance Facts Sheets)
  • “Experimental research on the effects of cannabis … indicat[e] that any effects … dissipate quickly after one hour.” (NHTSA. 2003. State of Knowledge of Drug-Impaired Driving: FINAL REPORT)
  • “[T]he cannabis effect (on driving performance) tends to disappear after the first 60 minutes of use.”  (Pulido et al., 2011. Cannabis use and traffic injuries.)

Cannabis-influenced changes in performance are typically subtle (particularly when compared to those associated w/ alcohol)

  • THC’s adverse effects on driving performance appear relatively small.” (Robbe. 1993. Marijuana and actual driving performance: Final report for DOT)
  • [M]ost marijuana-intoxicated drivers show only modest impairments on actual road tests. … Although cognitive studies suggest that cannabis use may lead to unsafe driving, experimental studies have suggested that it can have the opposite effect.” (Sewell et al., 2009. The effect of cannabis compared with alcohol on driving)
  • “Performance as rated on the Driving Proficiency Scale did not differ between treatments (cannabis versus placebo). It was concluded that the effects of low doses of THC … on higher-level driving skills as measured in the present study are minimal.” (Lamers et al., 2001. Visual search and urban driving under the influence of marijuana and alcohol.)

Experienced users tend to become tolerant to many of cannabis’ performance-impairing effects

  • [F]requent marijuana users may show fewer behavioral signs of disruption during intoxication than infrequent users, even when difficult memory tasks are used to assess cognitive performance.” (Hart et al., 2010. Neurophysiological and cognitive effects of marijuana in frequent users )
  • “The present study confirms that heavy cannabis users develop tolerance to some of the impairing behavioral effects of cannabis.” (Theunissen et al., 2011. Neurophysiological functioning of occasional and heavy cannabis users during THC intoxication)
  • “[T]he present study generally confirms that heavy cannabis users develop tolerance to the impairing effects of THC on neurocognitive task performance (Ramaekers et al., 2010. Tolerance and cross-tolerance to neurocognitive effects of THC and alcohol in heavy cannabis users)
  • Experienced smokers who drive on a set course show almost no functional impairment under the influence of marijuana.” (Sewell et al., op. cit.)

Combining alcohol with cannabis may increase psychomotor impairment in a synergistic manner

  • “This study demonstrates that cannabis impairs driving ability in a concentration-related manner. The effect is smaller than for ethanol. The effect of ethanol and cannabis taken simultaneously is additive.” (Bramness et al., 2010. Impairment due to cannabis and ethanol: clinical signs and additive effects)
  • “Experimental studies have shown alcohol and THC combined can produce severe performance impairment even when given at low doses. The combined effect of alcohol and cannabis on performance and crash risk appeared additive in nature, i.e. the effects of alcohol and cannabis combined were always comparable to the sum of the effects of alcohol and THC when given alone.” (Ramaekers et al., 2004. Dose related risk of motor vehicle crashes after cannabis use)

If you would like to schedule an initial consultation, contact a Colorado criminal defense attorney for issues regarding with your misdemeanor or felony. We represent clients in Gunbarrel, Colorado and surrounding area. The Savela Law Firm, P.C. Give us a call at (720) 260-7392 or complete our inquiry form.