Minnesota transportation officials say volunteers pick up an estimated 26,000 tons of trash along state highways each year. The Department of Transportation figures the volunteers save the state an estimated $6-million annually. The Adopt-A-Highway program is currently staffed with more than 49,000 volunteers who clean up litter from 11,000 miles of Minnesota highways. The program requires at least a 2-year commitment to pick up trash two or three times a year, and allows state road crews to spend more time on highway improvement and safety projects. Only state workers are responsible for picking up trash along the interstate.