Pubdate: Wed, 04 Jul 2012
Source: Standard-Times (New Bedford, MA)
Copyright: 2012 South Coast Media Group
Contact:  http://www.southcoasttoday.com/
Details: http://www.mapinc.org/media/422
Author: Robert Frichtel

MARIJUANA AS MEDICINE NEEDS RULES TO DRIVE BY

Let's start by stating that driving while impaired by drugs or 
alcohol is a crime and must be punished. All 50 U.S. states have 
clear laws prohibiting this activity.

But there is one intoxicant that is trickier than the others: 
marijuana, especially when used for medical purposes.

During the past two years, Colorado and Montana, along with more than 
a dozen other states, have proposed laws that set a strict threshold 
for determining when a marijuana user is deemed too impaired to 
drive. These would consider a concentration of more than 5 nanograms 
of tetrahydrocannabinol, or THC (the psychoactive component of 
marijuana) per milliliter of blood, as hands-down proof of 
intoxication or impairment.

The result would be an automatic guilty verdict, with all that 
entails: a temporary loss of driving privileges, fines, lawyer's 
fees, possible jail time and greatly increased insurance premiums. By 
some estimates, a conviction for driving under the influence can cost 
a driver as much as $10,000.

Several states are going further and have either adopted or are 
considering zero-tolerance laws for THC levels. This means any THC in 
the blood would result in a conviction.

Here's the problem with these laws: There are questions about how, 
and at what level, cannabis use impairs driving ability. For a 
patient in one of the 17 states where marijuana has been legalized 
for medicinal use, how are you to know when it's legal to drive? 
After consuming marijuana, should you wait 12 hours to drive or one 
day? When will your THC level be below the 5-nanogram threshold? The 
answer is complicated.

Although marijuana is readily detectable in toxicology tests of 
blood, hair, urine or saliva, what isn't clear is just how quickly 
THC passes through the body. We know, for example, that THC may be 
detected in the blood of occasional users several hours after 
ingesting. But in some chronic users there may be traces for days 
after the last use, long after any performance-impairing effects have subsided.

This is a very clear contrast with alcohol. There is a firm 
understanding of the rate at which the body metabolizes alcohol and 
there are well-known guidelines on how much time must pass after 
drinking before one is fit to drive. Tests can easily be administered 
in roadside stops. Those who fail simple benchmarks of sobriety -- 
not to mention breath tests -- are usually convicted or plead guilty.

The research on how marijuana affects driving is far less conclusive, though.

Testing done on drivers under the influence of alcohol often show 
that drivers display more aggressive behavior behind the wheel, and 
errors are more pronounced than when sober. The opposite tends to be 
true when drivers are under the influence of THC; they tend to have 
heightened awareness -- rather than diminished sensitivity as they do 
after drinking -- to their surroundings. As a result, they tend to 
compensate by driving more cautiously.

A 2007 control study published in the Canadian Journal of Public 
Health reviewed 10 years of U.S. auto-fatality data. Investigators 
found that U.S. drivers with blood-alcohol levels of 0.05 percent -- 
a level below the national 0.08 percent legal limit -- were three 
times as likely to have been driving unsafely before a fatal crash, 
compared with individuals who tested positive for marijuana.

What this means is that we need more research before new DUI 
marijuana laws are enacted. Setting an absolute impairment standard 
for THC bloodstream levels is premature. And these laws, which target 
marijuana use and associated medical marijuana patients, are discriminatory.

I say this at a time when there is an absence of legislation dealing 
with the use and well-documented abuse of prescription painkillers, 
which can dangerously impair the judgment needed for safe driving. 
State legislatures aren't setting arbitrary and scientifically 
unproven blood-level standards for these drugs. So why are they 
focused on marijuana?

Driving while intoxicated must anywhere and everywhere be illegal, 
whether that impairment is caused by prescription drugs, alcohol 
purchased at a liquor store or marijuana used on the recommendation 
of a doctor. Under current standards, someone can be charged with DUI 
for marijuana use based on roadside sobriety tests and observations 
by the arresting officer in conjunction with blood samples. Those 
tests serve their purpose at this point.

But if states are going to turn to strict threshold laws, they should 
answer this question: Based solely on THC concentrations in blood 
from marijuana, when is a driver too impaired to drive safely?

Until the evidence is in, it's hard to see why any state needs to 
lower the burden of proof necessary to convict someone of a DUI 
marijuana charge.
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MAP posted-by: Jay Bergstrom