Bulletin No. 32 of this office, entitled "Public Road Mileage, Revenues and Expenditures in the United States in 1904," has proved so useful that it has been decided to collect and publish similar information from time to time, in order to show what progress is being made in this respect. In pursuance of this plan, the office has just completed the collection and compilation of information showing the mileage of improved and unimproved roads in the United States for the year ending December 31, 1909, and in order to meet the numerous demands for information in regard to the cost of road building, considerable data have also been included on that subject. It is the purpose of this bulletin to assemble the results of this investigation in such a way as to illustrate the progress in road improvement in the different States for the five-year period from 1904 to 1909.