LAS VEGAS (KTNV) — Driving under the influence of marijuana is a crime in every state just like driving under the influence of alcohol.
Although the laws are pretty clear when it comes to driving under the influence of alcohol (states have established limitations on how much alcohol can be found in the blood), it’s not so clear with marijuana.
There are two types of DUIs — per se and impairment.
Per se laws establish that once a person is shown to have reached or surpassed the legal limit, that person will be considered impaired by law.
To prove a per se DUI, a prosecutor would simply need to produce blood test results that prove the driver was over the limit. If that is the case, the prosecutor is not required to prove if the driver was impaired or not.
For an impairment DUI, a prosecutor would have to prove that the driver was actually impaired. Proof that a driver was impaired in “any way” is enough for conviction in some states. But in other states, the prosecution has to prove the drive was significantly affected in order to obtain a conviction.
17 states have zero tolerance or non-zero per se laws for marijuana; 10 states have zero tolerance for THC or a metabolite; 3 states have zero tolerance for THC but no restriction on metabolites; 4 states have specific per se limits for THC; and 1 state (Colorado) has a permissible inference law for THC.
Nevada has a per se law (Nevada Revised Statute Section 484C.110) for those arrested for DUI with marijuana or marijuana metabolites in their system. Drivers are allowed to have 2ng of THC and 5ng of metabolite in their blood before being charged with a DUI.
The current law applies to both recreational and medical marijuana.
A new assembly bill (AB400) in front of the Nevada legislature would change the current law. At this time, if a certain level of THC is found in the blood or urine, a driver will be found guilty regardless if the person is impaired or not. Proponents of the bill argue that unlike alcohol, marijuana can stay in the system for as long as two weeks. So, even if a person has not used marijuana recently and are not under the influence, THC and metabolites can still show up in a test and the driver can be found guilty.
The Nevada Assembly approved the bill on April 20. It still has to be approved by the Senate and signed by Gov. Sisolak to become a law.
If the bill is signed into law, police will still be allowed to test a driver's blood for marijuana. However, a prosecutor would have to prove that the driver was actually impaired in order to secure a conviction.