61 STAT.] SOTH CONG. , 1 ST SESS.-CH. 324-JULY 25, 1947 interchangeable use of any of the same by officers and employees of the District, except as otherwise provided in this Act: Provided,That "official purposes" shall not apply to the Commissioners of the District of Columbia and in cases of officers and employees, the character of whose duties make such transportation necessary, and then only as to such latter cases when the same is approved by the Commissioners. No motor vehicles shall be transferred from the police or fire depart- ments to any other branch of the government of the District of Columbia. Operating expenses, Street and Bridge Divisions (payable from highway fund): For operating expenses of the Street and Bridge Divisions, including operation, minor construction, maintenance, and repair of bridges; repairs to streets, avenues, roads, sidewalks, and alleys; reconditioning existing gravel streets and roads; and cleaning snow and ice from streets, sidewalks, cross walks, and gutters, in the discretion of the Commissioners; such expenses to include purchase of passenger motor vehicles, surveying instruments, implements, and equipment used in this work: $1,858,000, of which amount $45,000 shall be exclusively for snow removal purposes: Provided, That the Commissioners are hereby authorized to purchase and install a municipal asphalt plant including all auxiliary plant equipment to be paid for from this appropriation at a cost not to exceed $150,000. Capital outlay, Street and Bridge Divisions (payable from highway fund): For expenses necessary for the grading, surfacing, paving, repaving, widening, altering, and otherwise improving streets, avenues, roads, and alleys, including curbing and gutters, directional and pedestrian islands at various intersections to permit of proper traffic- light control and channelization of traffic, drainage structures, culverts, suitable connections to storm-water sewer system, retaining walls, replacement and relocation of sewers, water mains, fire hydrants, traffic lights, street lights, fire-alarm boxes, police-patrol boxes, and curb-line trees, when necessary, Federal-aid highway projects under section 1 (b) of the Federal Aid Highway Act of 1938, and highway structure projects financed wholly from the highway fund upon the approval of plans for such structures by the Commissioners; for carry- ing out the provisions of existing laws which authorize the Commis- sioners to open, extend, straighten, or widen streets, avenues, roads, or highways, in accordance with the plan of the permanent system of highways for the District of Columbia, and alleys and minor streets, and for the establishment of building lines in the District of Columbia including the procurement of chains of title; and for assessment and permit work, paving of roadways under the permit system, and con- struction of sidewalks and curbs around public reservations and munic- ipal and United States buildings, including purchase or condemnation of streets, roads, and alleys, and of areas less than two hundred and fifty square feet at the intersection of streets, avenues, or roads in the District of Columbia, to be selected by the Commissioners $5,285,000, to remain available until June 30, 1949, and the limit of cost of the South Capitol Street Bridge as specified in the District of Columbia Appropriation Act, 1943, is increased to $5,400.000: Provided, That appropriations contained in this Act for highways, sewers, city refuse, and the Water Division shall be available for snow removal when ordered by the Commissioners in writing: Provided further, That in connection with the purchase and installation of a municipal asphalt plant on District owned property the Commissioners are authorized to make expenditures from this appropriation in an amount not exceeding $150,000 for the preparation of the site, including the construction of sea walls, dock facilities, and a railroad siding: Provided further, That in connection with the highway planning 441 Nonapplicability of "official purposes." Ante, p . 244. Snow removal. Municipal asphalt plant. 52 Stat. 633. 23 U. S. C. §41b. 56 Stat. 453. Snow removal. Municipal asphalt plant.