(Denver Post) A proposal at the state Capitol to set a limit for how stoned is too stoned to drive died this evening in the Senate.
In a crucial vote, lawmakers rejected a hard cap on the amount of THC — the psychoactive chemical in marijuana — drivers could have in their systems above which they would be presumed too high to drive. Instead, a divided Senate sided with medical-marijuana advocates, who urged more study of the proposal.
Echoing the concerns of a number of lawmakers, Aurora Democratic Sen. Morgan Carroll said she believes the research is inconclusive about how much THC definitively causes impairment, meaning a 5-nanogram limit might snare sober drivers while allowing stoned ones to go free.
“If you’re going to have a shortcut to presuming somebody is impaired, let’s make sure the science is established,” Carroll said.
This is wonderful news, because the science is really inconclusive about regular cannabis use and driving impairment. My colleague Paul Armentano just alerted me to a new study that differentiates between infrequent users and regular users:
It concludes: “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 cusers might exhibit measurable cannabinoid concentrations in blood, 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.”
This reaffirms, in greater detail than the 2009 paper by Karshner et al, the residual phenomenon and how this could confound proper interpretation in DUI per se states.
Or as we saw in the case of the WestWord’s pot critic, William Breathes, who tested at 13ng/ml after sixteen hours of non-use of cannabis. Regular users do develop a tolerance and do not eliminate THC at the same rates. Let’s judge driving impairment by demonstration and not by body chemistry.
Contact your elected representatives and urge them to 'Stop Arresting Marijuana Smokers'. 
[...] that I-502 is “throwing patients under the bus”. And let me just re-iterate that this standard is unscientific, unnecessary, and unjust. But let’s also re-iterate that the majority of tokers won’t be above 5ng/mL if they [...]
[...] “Heavy users might exhibit measurable cannabinoid concentrations in blood, even if the last cannabis use was more than 24 hours ago.” Colorado’s 5 ng/ml per se DUID bill dies again as new research backs higher thresholds for reg… [...]
[...] 1. Colorado’s 5ng/mL per se DUID bill dies again as new research backs higher thresholds for regu… [...]
[...] even as he was completely sober after a night of restful sleep. This front-page news and subsequent support from new studies and a deadlocked task force of experts forced the Colorado legislators to kill the proposal. [...]
[...] even as he was completely sober after a night of restful sleep. This front-page news and subsequent support from new studies and a deadlocked task force of experts forced the Colorado legislators to kill the proposal. [...]
[...] even as he was completely sober after a night of restful sleep. This front-page news and subsequent support from new studies and a deadlocked task force of experts forced the Colorado legislators to kill the proposal. [...]
[...] 1. Colorado’s 5ng/mL per se DUID bill dies again as new research backs higher thresholds for regular … [...]
[...] 1. Colorado’s 5ng/mL per se DUID bill dies again as new research backs higher thresholds for regular … [...]
[...] would proceed with such a scientifically-unjustifiable standard for driving under the influence. This same battle played out prominently in Colorado where a 5ng/ml standard was stopped when a local patient/reporter tested at 13.5ng/ml after fifteen [...]
[...] would proceed with such a scientifically-unjustifiable standard for driving under the influence. This same battle played out prominently in Colorado where a 5ng/ml standard was stopped when a local patient/reporter tested at 13.5ng/ml after fifteen [...]
[...] would proceed with such a scientifically-unjustifiable standard for driving under the influence. This same battle played out prominently in Colorado where a 5ng/ml standard was stopped when a local patient/reporter tested at 13.5ng/ml after [...]
[...] would proceed with such a scientifically-unjustifiable standard for driving under the influence. This same battle played out prominently in Colorado where a 5ng/ml standard was stopped when a local patient/reporter tested at 13.5ng/ml after fifteen [...]
[...] would proceed with such a scientifically-unjustifiable standard for driving under the influence. This same battle played out prominently in Colorado where a 5ng/ml standard was stopped when a local patient/reporter tested at 13.5ng/ml after fifteen [...]