ST. PAUL, Min. (MNN) -  The state Department of Transportation is looking for volunteers to help pick up litter along the highways. Around 45-hundred groups and organizations already participate in Minnesota's Adopt A Highway program.  Coordinator Ernest Lloyd says they're asking volunteers to adopt a two-mile stretch of roadway and clean it up three times a year.  MnDOT crews will pick up the trash and provide bags and safety vests.  Lloyd says volunteers clean up about 26-thousand tons of litter every year for an annual savings of five-million dollars.  MnDOT will erect a sign along each group's section of highway to recognize its efforts.