In California there is no per se or presumptive level of marijuana under the DUI laws. California Vehicle Code §23152 (a) states; it is unlawful for any person who is under the influence of any alcoholic beverage or drug, or under the combined influence of any alcoholic beverage and drug, to drive a vehicle. The Judicial Council of California had approved the following definition for under the influence, “a person is under the influence if, as a result of consuming and/or taking a drug, his or her mental or physical abilities are so impaired that he or she is no longer able to drive a vehicle with the caution of a sober person, using ordinary care, under similar circumstances. Marijuana or Cannabis is “Delta-9-Tetraydrocannabinol” (THC). THC is primarily metabolized to “11-hydroxy-THC (THC-OH or OH) which is psychoactive or active. The 11-Hydroxy-THC is then rapidly metabolized to the 11-nor-9-carboxy-THC (THC-COOH, THC-A or COOH) which is non-psychoactive or inactive. The primary ingredient in marijuana delta-9-tetrahydrocannabinol or “THC, lingers in the body long after the effects of ingesting marijuana wear off. The life span of THC ranges from hours to months, depending on a variety of issues, including; the amount of marijuana consumed, the concentration of the THC, and personal tolerance to marijuana. Recently in Colorado a proposal to set a limit for marijuana died. Lawmakers rejected a hard cap on the amount of THC — the psychoactive chemical in marijuana — drivers could have in their systems. The proposed limit of 5 nanograms per milliliter of blood brought concern since the research is inconclusive about how much THC definitively causes impairment. The Colorado proposal of a THC limit had passed in the House, 51-14, but failed in the Senate. Thus, given THC lingers in the body long after the effects of ingesting marijuana wear off, and the life span of THC ranges from hours to months, depending on the amount of marijuana consumed, the concentration, and personal tolerance to marijuana, a prosecution for DUI marijuana could be fraught with an array of problems.