A new meta-study published this month concluded that driving after using marijuana doubles the risk of a car crash, and opponents of legalization are already touting this as a reason to keep the drug illegal. Yet before there's a public uproar for stricter marijuana DUI laws, it's important to put things in perspective -- we must consider the risk involved and make sure the punishment fits the crime. While weak DUI laws clearly jeopardize public safety, overly strict rules or harsh penalties can ruin the lives of innocent drivers who aren't truly impaired.

Anything that doubles the risk of a car accident should be avoided, and no one is saying it's ok for people to drive after using marijuana. NORML has been telling smokers this for years, writing in their Principles of Responsible Cannabis Use, "The responsible cannabis consumer does not operate a motor vehicle or other dangerous machinery while impaired by cannabis, nor (like other responsible citizens) while impaired by any other substance or condition." Just like you shouldn't drive after drinking alcohol, you shouldn't drive after smoking cannabis.

But that's not to say marijuana impacts driving performance the same as alcohol. Driving under the influence of marijuana doubles your risk of a crash, while a just-barely-illegal .08 BAC increases your risk eleven-fold -- yet the penalties are the same. After Colorado voters legalized cannabis for adult use, the legislature voted to criminalize driving under the influence of marijuana, using 5 nanograms of THC per milliliter of blood as the cut-off point for impairment (which is problematic for a host of reasons, and daily users have tested as high as 13.5 ng/ml while completely sober). Drivers found to be impaired by marijuana are charged with the same crime as drunk drivers, making it impossible to separately analyze the data, and applying the same punishments to two behaviors with very different levels of risk.

In comparison, studies have shown that texting while driving similarly doubles the risk of a crash, and making phone calls actually triples it. And how are those risky behaviors dealt with? Colorado did ban texting while driving in 2009, with first offenses punished with a $50 ticket and second offenses jumping to $100. This year, a bill to widen the scope of that law to include phone calls was rejected by the state legislature.

Punishments for driving under the influence of marijuana are exponentially harsher. Aside from the burden of a criminal record, a first marijuana DUI conviction in Colorado comes with a minimum five days in jail, $600 fine, and 48 hours of community service. These can go as high as a year in jail, $1000 fine, 96 hours of service, and two years of probation. As part of its educational campaigns, the state of Colorado touts how costly a DUI can be: when considering legal fees, increased insurance premiums, and other associated expenses, a first offense costs about $10,270 -- over 200 times the cost of a first offense of texting while driving, which studies say is just as dangerous. No evidence supports this gaping difference; the law was more a knee-jerk reaction by the legislature than a reasoned deliberation.

The War on Drugs has been an undeniable failure, and regulating marijuana like alcohol is a big step toward a more sensible approach to drugs in our country. But as we update our policies, let's ensure they also recognize that marijuana and alcohol are different in many ways. DUI laws should be based on actual risk, not political expediency.

This is not to deny that impaired driving is a huge problem -- drunk driving alone killed over 10,000 Americans in 2012, and texting-related accidents have soared in recent years. So how best to deal with marijuana-impaired driving as more states legalize the drug? States should begin by separating marijuana DUI from alcohol DUI so researchers can better study legalization's effects. When deciding punishments, legislators should take into consideration the relative danger of various forms of impairment, from texting to marijuana to alcohol. And to ensure that no sober drivers are wrongly convicted, states should judge impairment by field sobriety tests of motor skills and brain function rather than arbitrary concentrations of THC in the bloodstream. Taken together, these reforms will keep our roads safe while minimizing any potential side effects.