BUREAU OF PUBLIC EOADS. 499 



With these several considerations in mind the initial decision as 

 to the type of a particular road is made by the State highway depart- 

 ment. Its decision is reviewed by the bureau after an independent 

 study of the conditions, and the type of road finally decided upon 

 is that type which in the judgment of the engineers of the State 

 department and of this bureau is the most suitable under the cir- 

 cumstances. 



The tj^pes of road selected and constructed in this manner have in- 

 cluded practicalh^ all the well-known forms of construction from unsur- 

 faced earth roads to high-class concrete, brick, and bituminous concrete 

 roads. In point of mileage the low types of earth, sand clay, and 

 gravel represent about 66 per cent of all the roads constructed : the 

 intermediate types of water-bound macadam and bituminous 

 macadam, etc., constitute onl}^ about 7 per cent; and the high types 

 of concrete, brick, bituminous concrete, etc. (including a considerable 

 mileage the type of which has not been definitely decided, but which 

 will be surfaced with one of the higher types of pavement), involve 

 about 24 per cent of the total mileage. 



A hasty conclusion drawn from these statistics might make it 

 appear that the Federal funds are being spent -to too great an extent 

 on roads of relatively unsubstantial character. On the contrary, the 

 bulk of the money is being expended for roads of the high and inter- 

 mediate type — 60 per cent for the former and 9 per cent for the 

 latter — and only about one-quarter of the money allotted has gone 

 for the roads of the lower type, which constitute 66 per cent of the 

 mileage. Not only, however, is the major portion of the Federal 

 money expended for roads of the higher type, but the roads them- 

 selves are of distinctly higher type, in the average, than the roads 

 constructed by the State highway departments. 



The following table shows the classified mileage of roads super- 

 vised by the State highway departments during the calendar year 

 1919, as reported to this bureau by the several departments. In the 

 parallel columns the mileage of the types of Federal-aid road is re- 

 peated for purposes of comparison. JPerccntages of each type and 

 each class are shown for the Federal and State roads. It willbe clear 

 from an examination of this table that the Federal-aid roads are rela- 

 tively more substantial in the average than tlie roads built under 

 State supervision alone. 



