Eastern Idaho police say a growing number of Montana motorists pulled over for speeding are also being charged for having marijuana in their vehicles. Many of the Montana drivers charged in recent weeks have valid Montana permits to possess marijuana for medical reasons. But Idaho authorities say the right for someone to possess marijuana for medical reasons in Montana doesn't apply in the Gem State. Last week alone, The Rexburg Standard Journal reported four Montana motorists were charged in Fremont County with possession of marijuana or drug paraphernalia. Fremont County Sheriff Department Chief Deputy Kurt Hillman says speeding or other traffic violations give deputies opportunity to look for other violations of the law. Hillman's message to Montana motorists authorized to legally carry marijuana: Drive the speed limit on Idaho roadways.