The department shall investigate and determine upon the various methods of road construction best adapted to the various sections of the State; and establish standards for the construction and maintenance of highways in various sections, taking into consideration the topography of the country, the natural conditions and the character and availability of road building material, and the ability of the townships and counties to build and maintain roads under the provisions of this act. The department may at all reasonable times be consulted by county, city, borough, incorporated town, or township officers having authority over highways and bridges, and shall, when requested, advise and give information to such officers relative to the construction, repairing, alteration, and maintenance of highways and bridges. The department shall at all times lend its aid in promoting road improvement throughout the State, and may prepare models and pictures for exhibition, and exhibit the same at such times and at such places as in its judgment shall be deemed advisable, and, in addition thereto, the department may also compile all useful information relative to road building and maintenance, which it shall disseminate by means of printed bulletins, issued at such times and in such numbers as it shall deem best. The department shall publish maps showing complete road surveys of each county, which shall be kept on sale in the department at cost of publication. Such maps shall be published at such times and in such form as shall be determined by the secretary.