Section 1. It is hereby declared to be the policy of the commonwealth to regulate transportation of property by motor carriers upon its ways in such manner as to recognize and preserve the inherent advantages of such transportation, and to foster sound economic conditions in such transportation and among carriers engaged therein in the public interest; and in connection therewith to: (1) Promote adequate, economical and efficient service by motor carriers, and reasonable charges therefor, without unjust discriminations undue preferences or advantages or unfair or destructive competitive practices, (2) improve the relations between, and co-ordinate transportation by and regulation of, motor carriers and other carriers, (3) develop and preserve a highway transportation system properly adapted to the needs of the commerce of the commonwealth, and (4) promote safety upon its ways in the interests of its citizens.