Said sum shall be distributed to the towns as follows, provided the amount of each such distribution shall be reduced proportionately in the event that the total of all such distributions exceeds the amount appropriated for the purposes of § 13a-175a: One thousand five hundred dollars per mile shall be paid for each mile of improved roads for the first thirty-two miles thereof and the remaining allocation shall be distributed pro rata to the towns on the basis of the ratio of the population of the town to the population of the state. The figures promulgated by the Department of Vital Statistics of the Connecticut Department of Public Health for the immediately preceding year shall be used to determine a town’s population. Any town which would be allocated less under the provisions of this section than such town was allocated for the fiscal year 1966-1967 under § 13a-169 prior to July 1, 1967, shall be paid, from funds appropriated to the Commissioner of Transportation, in addition to the allocation provided herein, an amount equal to the difference between said allocation and the amount allocated to such town for said fiscal year. The commissioner and the selectmen of each town shall ascertain the number of miles of such improved highways in such town. Cities and boroughs not consolidated with their towns, and having responsibility for construction or maintenance of public roads, shall receive a pro rata share of the sum allotted to the town, such share to be computed in the ratio of the population within the city or borough to the total population in the town. If the commissioner and selectmen of any town are unable to agree on the number of miles of improved highways in such town, the commissioner shall determine the number of miles of such improved highways in such town. Any town aggrieved by the action of the commissioner may appeal therefrom in accordance with the provisions of § 4-183.