((a)) ** .—** The Secretary of Transportation may investigate and report on the need for regulation by the United States Government of sizes, weight, and combinations of motor vehicles and qualifications and maximum hours of service of employees of a motor carrier subject to subchapter I of chapter 135 of this title and a motor private carrier. The Secretary shall use the services of each department, agency, or instrumentality of the Government and each organization of motor carriers having special knowledge of a matter being investigated.

((b)) ** .—** In carrying out this chapter, the Secretary may use the services of a department, agency, or instrumentality of the Government having special knowledge about safety, to conduct scientific and technical research, investigation, and testing when necessary to promote safety of operation and equipment of motor vehicles. The Secretary may reimburse the department, agency, or instrumentality for the services provided.