How much marijuana makes someone too impaired to drive a vehicle?

The answer isn’t easy to find, but it’s one more than 100 lawmakers are set on finding.

The Michigan House are seeking a study to find the “magic number” of how much marijuana in a driver’s blood means the person is impaired, a decision that currently falls to Michigan courts and juries.

While supporters look for a threshold based on a standard measurement of active THC (the main ingredient in marijuana) per milliliter of blood to catch drivers stoned to impairment, detractors say it’€™s not that simple. Marijuana interacts differently with a person’s body compared to alcohol, critics say, making it harder to measure for and determine impairment.

State Rep. Peter Lucido, R-Shelby Township, is the sponsor of the bill to create the study commission. He said other states have a set threshold for driving under the influence of marijuana — 5 nanograms of active THC per milliliter of blood in Colorado —  but they pulled those numbers “€œout of their derrieres.” [Read more at MLive.com]