Former Secretary of Transportation William T. Coleman Jr., and his deputy secretary. John W. Barnum, proposed a sweeping reorganization of their 10-year old department as a farewell gift to the reorganization-minded Carter administration.

In a 54-page report dated Jan. 19, the last full day in office for the administration of former president Ford, Coleman and Barnum advocated consolidation of many programs under two new DOT divisions - one for interstate transportation and one for local transportation.

In addition, they recommended a new motor vehicle administration and establishment of a unified transportation budget to replace the splintered accounts now on government books for various programs.

From other agencies and departments throughout Washington, the former officials recommended inclusion in a reorganized DOT of the Commerce Department's Maritime Administration, the Civil Aeronauties Board local air service subsidy and international aviation policy programs, the Interstate Commerce Commission's freight car movement supervision, and some regulatory and research activities related to motor vehicles now included in the Environmental Protection Agency and Energy Research and Development Administration.

"The primary purposes of our recommended changes are to establish an organizational structure that would permit the federal government and the Congress to focus more sharply on spending decisions that affect the development of the national transportation system and . . . to establish a mechanism that would give state and local governments greater flexibility in using federal financial assistance," Coleman and Barnum said in their report, copies of which were made available over the weekend by Barnum.

Left untouched by the proposal would by DOT's Federal Aviation Administration (except that its program of grants for airport construction would go to the new local and interstate administrations). the U.S. Coast Guard and the St. Lawrence Seaway Development Corp.

Coleman and Barnum urged continuation of highway and aviation user charges and installation of inland waterway user charges, to pay for part of the expense nwo borne by tax-payers in operating and expanding the waterway system.

Proposed taxes on petroleum used in transportation or an increase in current motor vehicle fuel taxes should be imposed solely for the purpose of funding a trust fund for all transportation, they said.

Under the Coleman-Barnum plan, the principal consolidations would create:

An Interstate Transportation Aministration, to supervise the interstate highway system, Amtrak, the Northeast rail corridor rehabilitation, intercity rail freight service, pipeline safety, Corps of Engineers programs for ports and inland waterways and medium and large hub airport development.

A Local Transportation Administration, including parts of th highway system in urban areas, urban mass transit aid, terminals for use by several forms of transportation, rural highway aid, rail branch line assistance and local air service subsidies.

The Motor Vehicle Administration, including driver safety, auto safety and all programs under the Highway Safety Act.

Gone under this plan would be such agencies as the Federal Railroad Administration, National Highway Transportation and Safety Administration, Federal Highway Administration and Urban Mass transportation Administration.