Jefferson County Board of Supervisors approved speed limits of 45 mph on 170th Street between Juniper and Iris avenues and on Jasmine Avenue between 170th and 180th streets.?I did a study that shows the area has the character of a suburban area and the 55 mph speed limit can be lowered to 45 mph,? said Jefferson County Engineer Scott Cline Monday at the regular board meeting.?Next summer the Department of ...