What are the Dangers of Driving After Smoking Marijuana?
There are several specific dangers related to driving after smoking marijuana, including the following:
- Slowed reaction times
- Impaired judgment
- Impaired distance and time judgment
- Decreased coordination
- Increase in lane weaving, according to one study
- Altered attention to the road
- Possible drowsiness
How Common Is Finding Marijuana in the Blood of a Driver Involved In A Crash?
After alcohol, marijuana is the drug most often found in the blood of drivers involved in crashes. The effects of specific drugs differ, depending on how they act in the brain; while marijuana can decrease coordination, slow reaction times and impair judgment to some extent, cocaine and methamphetamine can cause a driver to exhibit reckless or aggressive behaviors, and benzodiazepine use can lead to drowsiness or dizziness.
Any one of these types of impairments can cause a driver to be involved in an auto crash. A 2010 nationwide study of deadly crashes found that 47 percent of drivers who tested positive for drugs had used a prescription drug, compared to 37 percent who had used marijuana (although possibly not on the day of the crash). Additional statistics regarding driving and cannabis use include:
- Surprisingly, in 2010, more than 25 percent of drugged drivers who were involved in a deadly crash were 50 years or older
- Illicit drug use—for all drugs, including marijuana—in adults between the ages of 50 and 59 has more than doubled since 2002.
- Among younger drivers—particularly college-age students—marijuana was the most common drug used, followed by cocaine and prescription pain relievers.
- A 2011 survey of middle and high school students showed that 12 percent of high school seniors had driven after using marijuana within the past two weeks, while 9 percent had driven after drinking alcohol.
How Many Crashes are Attributable to Marijuana Use?
It is difficult, if not impossible, to determine how many crashes are attributable to marijuana, for a variety of reasons. Because marijuana is often mixed with alcohol or other drugs, it can be difficult to definitively say whether a crash is actually caused by marijuana use. Further, among those whose body fluids are tested after a crash, a positive finding of marijuana can have little meaning, due to the fact that marijuana can be detected in body fluids for days or weeks after the actual use. The risks associated with smoking marijuana in combination with alcohol, cocaine or benzodiazepines appears to be far greater than for marijuana on its own.
One study found that the percentage of drivers involved in fatal crashes who had traces of marijuana in their blood has doubled in Washington state since marijuana was legalized in that state.
Are There Accurate Tests for Detecting Marijuana Use in a Driver?
The science simply is not clear regarding how to measure a driver’s “high,” and what constitutes driving high. While a person’s BAC is a fairly reliable indicator of driving deficiencies, marijuana-induced impairment occurs when the fatty tissues of the brain absorb the THC, yet THC levels in the blood can actually spike prior to the peak effects of the drug. Tests for detecting marijuana in the blood of a driver involved in a crash measure the level of delta-9-tetrahydrocannabinaol (THC), however a good roadside test for marijuana levels (or any other drug) does not currently exist. Some states have a zero-tolerance policy for any level of illicit drug in the bloodstream and can charge a DUI for any leveln the state of Colorado, drivers with five nanograms of active THC in their whole blood can be prosecuted for DUI. That being said, no matter the level of THC, Colorado law enforcement can arrest you based on observed impairment.
In another study, drivers who were determined to be impaired during traffic stops were given field sobriety tests, then those who did not pass the tests were given blood tests. In this particular study, 70 percent of the drivers who were found to be impaired by marijuana, still had THC blood levels lower than five nanograms per milliliter. This led researchers to believe there is no specific number for marijuana which can reliably predict impairment. Some believe laws should be passed that state if any marijuana is found in the body of the driver, the driver’s attorney would have to prove the drug was not the cause of the person’s impaired driving.
Should You Wait a Certain Length of Time Prior to Driving If You Have Smoked Marijuana?
Although there are many different opinions about how long you should wait after smoking marijuana to drive, some believe those under the influence of marijuana are actually more careful drivers. The bulk of the data on the issue does not necessarily prove that legalizing marijuana worsens road safety in any measurable way, and it is possible that police are simply testing for THC more in the states which have legalized the drug. This increased level of testing could be finding drivers who were missed in previous years, although it is also entirely possible that those with detectable levels of THC in their blood were not impaired at the time of a crash. Generally speaking, it seems to make sense to wait at least until the next day before you get behind the wheel, even after smoking a small amount of marijuana.
Is Driving While High Still a DUI?
DUI is driving under the influence, therefore can encompass driving under the influence of alcohol, drugs, or a combination. It can be much more difficult to prove a driver is under the influence of drugs than alcohol. Police officers typically do not test for drugs if the driver has a high enough BAC since there is already sufficient evidence for a DUI charge. It is important to note that in the state of Colorado, you could also be charged with child abuse if children are present in the vehicle and you are found to have marijuana in your system.
Studies Involving Driving and Cannabis Use
There are definitely mixed messages from different studies on marijuana use and driving. While some studies have shown drivers with THC in their blood were twice as likely to be responsible for a deadly crash than drivers who had not used drugs or alcohol, a large NHTSA study found no significant increased crash risk traceable to marijuana after controlling for age, gender, race, and presence of alcohol. A 2015 study published in the Journal of Drug and Alcohol Dependence, found that in driving simulators, those who were high were much less likely to weave in and out of their lane or to exceed the speed limit than those who were drunk.
What to Do if You are Pulled Over After Smoking Marijuana
If you are stopped after you have been smoking marijuana, you should not talk to the police other than providing your driver’s license and registration. You are within your rights to refuse field sobriety tests, and there are no penalties for doing so. However, refusing a blood test could result in your driving privileges being revoked. Further, if you refuse a blood test in the state of Colorado, you could be considered a high-risk driver, leading to administrative consequences such as a mandatory ignition interlock and criminal penalties. Avoiding a marijuana DUI is your best bet, and you can do so by always having a designated driver, or by taking a taxi or a rideshare such as Lyft or Uber. By knowing the risks and the consequences of drugged driving ahead of time, you can avoid a Colorado DUI.
What to Do If You Receive a DUI After Smoking Marijuana
If you are charged with DUI after smoking marijuana, it is imperative that you contact an attorney as soon as possible. You need someone in your corner who will ensure your rights are protected throughout the process and who understands what you have at stake. An experienced DUI attorney will guide you through the process, making sure you understand all your options and help you achieve the best outcome possible.
Author Bio: Dianne Sawaya is a personal injury lawyer and founder of The Law Offices of Dianne Sawaya. Dianne founded her law firm in 2005 in order to bring a more personal approach to the law for her personal injury clients.