The chief enforcement officer and the inspectors, employed pursuant to the authority granted in Section 77-1-21, shall be responsible for enforcing and investigating all alleged violations of this chapter, and the rules, regulations and general orders of the commission promulgated thereunder. In the performance of their duties such employees shall give particular attention to the enforcement of the commission's safety rules and regulations; the provisions of this chapter applicable to rates, charges and practices of motor carriers; the provisions prohibiting unlawful preference, concession, rebate, or discrimination; the adequacy of service, equipment and facilities of motor carriers; and the requirements respecting certificate of public convenience and necessity or permits as set forth in this chapter.