The Triple A is warning people about legalized marijuana in Washington after an increase in fatal car crashes in which a driver tested positive for marijuana.

FOX's Jessica Rosenthal reports the Triple A also says marijuana DUI tests are unreliable in determining impairment:

In 2014 Washington state patrol reports 99 fatal crashes in which a driver tested positive for marijuana, compared to 63 in 2013 and 89 in the year 2011. Voters chose to legalize recreational use in 2012.

Dr. Stacy Hoff at the Traffic Safety Commission says DUI testing shows more people are positive for THC:

(Dr. Hoff) "But those increases in 2014 mostly occurred prior to retail sales opened, the marijuana involvement in the 2015 crashes is the same as it was in 2014."

And she says fatal crashes have actually increased nationwide. The Triple A themselves say it's not possible to set a blood-test level for THC that can reliably show impairment.

Jessica Rosenthal, FOX News.

Follow Jessica Rosenthal on Twitter: @JessicaFOXNews