Having reviewed research in this area, there is no scientific basis for a 5 nanogram limit on THC in Colorado. It is a futile attempt to treat marijuana the same as alcohol, although the science demonstrates that the way alcohol and THC enter the body and affect a person are considerably different. Research also demonstrates that regular users of marijuana can report a 5 nanogram result without there being any impairment. While a permissible inference is better than strict liability, these inferences are frequently given substantial weight by juries. It is frustrating that this same statute was rejected in committee after hearing evidence, but was later attached to another bill and avoided scientific scrutiny.
While driving while under the influence of THC should be subject to criminal penalties, this statute is not based on any scientific research and is nothing more than an attempt to place artificial limits on consumption to make it easier to prosecute.