462 ANNUAL EEPORTS OF DEPARTMENT OF AGRICULTURE. 



In this development the adoption of the Federal-aid highway 

 system provided for by the Federal highway act and the significant 

 researches of the past year constitute the greatest forward steps 

 that have ever been made. 



THE FEDERAL HIGHWAY ACT. 



The Federal highway act, approved November 9, 1921, provided 

 for the establishment of a system of public highways the mileage of 

 which shall not exceed 7 per cent of the total highway mileage in 

 any State. The act requires the division of the highways of this 

 system into primary or interstate and secondary or intercounty 

 highways, and limits the expenditure of all future Federal-aid appor- 

 tionments to this system. The act prescribes that the primary 

 highways shall not exceed three-sevenths of the total mileage which 

 may receive Federal aid and that the secondary highways shall con- 

 nect or correlate with the primary. It also indicates that the sys- 

 tems in adjoining States shall be correlated. 



The selection of 7 per cent of the roads of the Nation for future 

 systematic improvement is unquestionably the largest and most 

 important task ever assigned to the bureau. Its successful accom- 

 plishment predicated an unusual knowledge of agricultm-al, industrial, 

 and traffic development throughout the country and demanded as 

 an indispensable condition cooperation of the closest and most 

 sympathetic kind with all of the States. The terms of the act are 

 brief and general and the conditions actually existing in the United 

 States vary within wide limits, so that it has required very careful 

 study and adjustment to arrange for the designation and approval 

 of the system of roads required by the law. Immediately on the 

 passage of the act this feature of the law was taken under careful 

 consideration and in December, 1921, the first instructions were 

 issued providing for the submission by each of the States of tentative 

 Federal-aid systems within the State. In this way an initial expres- 

 sion of opinion and the result of the studies of the several State 

 highway departments were secured. 



Arrangements were then made for conferences between highway 

 officials representing adjacent States in order to secure correlation of 

 the roads suggested for the State systems. These conferences are 

 being followed by other conferences in each Federal-aid district, at 

 which necessary adjustments will be made to bring the designated 

 routes into entire and detailed harmony with the requirements of 

 the law. 



At the end of the fiscal year tentative maps showing the systems 

 proposed by the several States had been received from all States 

 except Alabama, Indiana, Minnesota, Mississippi, Missouri, Penn- 

 sylvania, South Dakota, Vu'ginia, and Wisconsm, and the first gen- 

 eral conference of the States in a field district had been held at Troy, 

 N. Y., at which the tentative systems were correlated for all of New 

 England, New York, and New Jersey. 



As an example of the difficulties which have to be overcome prior 

 to the approval of such a system of roads as the law requires is that 

 found in States where road construction is well advanced. In such 

 States a large percentage of the principal roads has been improved, 



