Question When coupling, you should: Answers Make sure to couple the proper glad hands. Only couple one set of glad hands. It is best to leave one glad hand loose. Explanation When coupling air brake hoses, you should make sure the proper pairs of gland hands are connected. They are sometimes color-coded to help drivers avoid mistakes. Typically, blue is used for service lines and red is used for emergency lines. This questions appears in the following tests: Alaska Combination Arkansas Combination Kentucky Combination Maryland Combination Mississippi Double New Mexico Combination Oklahoma Double South Carolina Double Utah Combination Virginia Combination Virginia Combination