# Marijuana DUI **URL:** \ **Category:** Factual Questions\ **Created:** [October 7, 2016, 2:31pm UTC](https://boards.straightdope.com/t/marijuana-dui/767842 "2016-10-07T14:31:28Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![boffking](https://avatars.discourse-cdn.com/v4/letter/b/858c86/32.png) [@boffking](https://boards.straightdope.com/u/boffking)\ **Post date:** [October 7, 2016, 2:31pm UTC](https://boards.straightdope.com/t/marijuana-dui/767842/1 "2016-10-07T14:31:28Z")
I am asking because of Maine’s referendum to legalize marijuana. I am in favor of this, but I am wondering if there has been a safe limit determined for someone to drive. Currently in Maine, there is technically a zero tolerance policy for driving while stoned, although I do not know how often it is actually enforced. If you test positive for marijuana at all, while driving, you can be charged with DUI. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [October 7, 2016, 2:46pm UTC](https://boards.straightdope.com/t/marijuana-dui/767842/2 "2016-10-07T14:46:22Z")
I think that the roadside tests give a negative or a positive result. Any positive will likely result in a prosecution. This is from Australia, but the situation here in the UK is pretty similar: > [@](#): > > Which drugs can be detected by random roadside saliva tests? > > Random roadside saliva tests can detect the presence of THC (cannabis), Methylamphetamine (speed) and MDMA (ecstasy). > > The devices used are able to detect THC (active component in cannabis) for several hours after use. The exact time will vary depending on the amount and potency of the cannabis used and the individual metabolism. Inactive THC residue in the body of a driver from use in previous days or weeks will not be detected. > > Methylamphetamine (speed) and MDMA (ecstasy) may be detected for approximately 24 hours after use. Again, the exact time will vary depending on the size of the dose, other drugs taken at the same time, as well as differences in individual metabolism. > > [http://www.dpti.sa.gov.au/towardszerotogether/Safer\_behaviours/Drug\_driving2/drug\_driving\_faqs](http://www.dpti.sa.gov.au/towardszerotogether/Safer_behaviours/Drug_driving2/drug_driving_faqs) ---
**Author:** ![jtur88](https://avatars.discourse-cdn.com/v4/letter/j/e9c0ed/32.png) [@jtur88](https://boards.straightdope.com/u/jtur88)\ **Post date:** [October 7, 2016, 3:57pm UTC](https://boards.straightdope.com/t/marijuana-dui/767842/3 "2016-10-07T15:57:21Z")
I believe DUI stands for “driving under the influence”, as opposed to DWI, “driving while intoxicated”. If you are under the influence of any substance that substantially reduces your capacity to drive safely, you are DUI, regardless of the legality of the substance. Generaly, the interpretation of DUI is to be driving in such an erratic manner as to attract the attention of the police, following the ingestion of any substance known to have such an effect. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [October 7, 2016, 4:13pm UTC](https://boards.straightdope.com/t/marijuana-dui/767842/4 "2016-10-07T16:13:39Z")
In Washington, where marijuana is legal, there is a concentration limit of 5 nanograms of THC in the blood. ---
**Author:** ![boffking](https://avatars.discourse-cdn.com/v4/letter/b/858c86/32.png) [@boffking](https://boards.straightdope.com/u/boffking)\ **Post date:** [October 8, 2016, 3:11am UTC](https://boards.straightdope.com/t/marijuana-dui/767842/5 "2016-10-08T03:11:22Z")
> [@bob\_2](#): > > I think that the roadside tests give a negative or a positive result. Any positive will likely result in a prosecution. > > This is from Australia, but the situation here in the UK is pretty similar: This is also how the law currently works in Maine. ---
**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\ **Post date:** [October 8, 2016, 11:35am UTC](https://boards.straightdope.com/t/marijuana-dui/767842/6 "2016-10-08T11:35:55Z")
> [@jtur88](#): > > I believe DUI stands for “driving under the influence”, as opposed to DWI, “driving while intoxicated”. If you are under the influence of any substance that substantially reduces your capacity to drive safely, you are DUI, regardless of the legality of the substance. Generaly, the interpretation of DUI is to be driving in such an erratic manner as to attract the attention of the police, following the ingestion of any substance known to have such an effect. Quite right. I have been given medications, legally prescribed by my doctor, where he carefully warns me that I can’t drive for several hours after taking them. If I ignored that and drove and was stopped, I could certainly be given a DUI ticket. ---
**Author:** ![racer72](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/racer72/32/3075_2.png) [@racer72](https://boards.straightdope.com/u/racer72)\ **Post date:** [October 8, 2016, 3:55pm UTC](https://boards.straightdope.com/t/marijuana-dui/767842/7 "2016-10-08T15:55:59Z")
> [@Johnny\_L.A](#): > > In Washington, where marijuana is legal, there is a concentration limit of 5 nanograms of THC in the blood. And you will be transported to a hospital for a blood test to check this, as my brother found out the hard way.