90 CONFERENCE OF GOVERNORS. 



work is done by a private contractor. They are all required to 

 come up to the same standard of excellence; and if any failure 

 of a road occurs, it must be due presumably to faulty design rather 

 than to execution. 



It is firmly the belief of this commission that in the construction 

 of a road the traffic conditions should be given first consideration; 

 in other words, where it might be necessary to build the strongest 

 kind of a trap rock macadam road in the neighborhood of popu- 

 lous towns and manufacturiag communities, it would be wholly 

 unnecessary and unwise to use the same method of construction 

 in the gravelly hills of the interior of the State or in reconstructing 

 the sandy roads of Cape Cod. 



Distributed through all of New England suitable stone for 

 macadam road purposes exists; the use to which any particular 

 material is to be put must determine whether it is fit or otherwise. 

 It is manifestly improper to use a soft limestone or sandstone, 

 or even granite, where constant or heavy traffic prevails. The 

 hard, close-grained trap that is found in Massachusetts, princi- 

 pally along the Connecticut Eiver and the Atlantic coast, is the 

 only material that withstands the wear and tear of our most heavily 

 used State roads; and this must be bound by some tenacious ma- 

 terial on the surface, to prevent its disintegration on curves or 

 exposed places under the swift-moviag automobile. For the or- 

 dinary country thoroughfare the softer stones that are found in 

 the fields or local quarries are sufiicient, and ia places preferable 

 to the harder stone; for under light trafiic the softer stone is less 

 liable to ravel, and the dust caused by attrition in a measure pro- 

 tects the road itself. 



The commission in its design has determined that the question 

 of foundation is subject wholly to the local conditions: that is 

 to say, in a clay soil, or a soil that is composed of alluvium or 

 sandy loam, a stone foundation is usually necessary; and that 

 where the underneath soil is of gravel or coarse sand, no founda- 

 tion whatever is necessary. It very often happens that a coarse 

 gravel may well take the place of the stone in foundations. 



It has been found that the ordinary country road should have a 

 hardened surface 15 feet wide, of either gravel or macadam, 

 with a shoulder of 3 feet on each side, conforming to the cross- 

 section of the hardened way, thus making a traversable road 21 

 feet wide. This marks the location of the gutters on either side, 

 and the embankment, either in cut or fill beyond this, should not 

 be at a steeper slope than ly^ horizontal to 1 vertical. 



