Pubdate: Thu, 11 Dec 2014 Source: San Diego Union Tribune (CA) Copyright: 2014 Union-Tribune Publishing Co. Contact: http://www.utsandiego.com/ Details: http://www.mapinc.org/media/386 Note: Seldom prints LTEs from outside it's circulation area. Author: Linda P. Hughes Referenced: http://www.mapinc.org/drugnews/v14/n909/a04.html STANDARD FOR DRIVING STONED NOT POSSIBLE While having uniform standards to determine whether driving is impaired by ingestion of marijuana ("How stoned is too stoned to drive?" Dec. 7) would greatly assist law-enforcement, it seems doubtful that any can be created that will be applicable across the broad spectrum of individuals. There are simply too many variables. Unlike alcohol, which can be proven to metabolize at a predictable rate, the THC in cannabis stays in the body for a long time and no studies have provided guidance in how to equate test-levels with degrees of impairment for driving purposes. This is not to say that pot combined with alcohol doesn't produce an undesirable effect on the ability to drive safely and prudently; it does. But that should not lead to blanket assumptions about cannabis alone and driving. Linda P. Hughes Lakeside - --- MAP posted-by: Jay Bergstrom