11.—40.

The rural roading system of the Dominion comprises 46,088 miles of formed roads, made up as folloWS Miles. Dustless surfaced roads .. .. •• •• •• on'iiq Metal- or gravel-surfaced roads .. .. •• •• • • Unsurfaced roads .. .. • • • • • ■ • ■ " ' Total .. 46 > 088 As the result of investigations carried out by the Department, it is estimated that the average surface thickness of the metal- or gravel-surfaced roads is under 4 in., and the following table shows the surface thickness required for the various allowable gross loads under the different c asses .

Assuming that the average width of metal surface is 11 ft., and the present average thickness of the surface is 4 in., then, estimating the cost of metal or gravel in place at 10s. per cubic yard, the cost of bringing the metal- or gravel-surfaced roads up to the various standards is shown m the following table

The above figures show that it would cost this country over 14 million pounds, or just under 2| million pounds per annum in capital charges on metal or gravel alone, to strengthen the surfaced rural roads so that they would be suitable for regular gross loads of 10 tons on two-axled heavy motor-vehicles. If, however, the maximum standard aimed at is Class 111, these ultimate costs would be halved, assuming that all the surfaced roads were brought to that standard ; but if the roadclassification is based on road-transport requirements, then Class IV and Class V roads will form a large proportion of the total mileage and the capital costs would be further materially reduced. In order that this problem of road standards may be attacked, it is essential that a comprehensive road census be carried out, and from the information derived from such a, census it would then be possible to lay down a definite national scheme of road-classification which, as previously pointed out, would result, in very substantial savings in road-construction costs without materially affecting the efficiency of road transport. In this connection it might be pointed out that the taking of a road census would be an eminently suitable work for the unemployed, supervised by Government and local-body engineers. The present position as regards classification of the rural roads is as under .

8

Allowable Gross Weights Maximum allowable Axle- Q om p ac ted Thickness of Classification of Road. for Two-axled Heavy , loads for Two-axled Surface required. Motor-vehicles. | Heavy Motor-vehicles. | Tons. Tons. Inches. Unclassified.. .. .. 10-0 , 7 Class II 8-0 • 6-4 ' Class III ., .. .. 6-5 ! 5-2 £ Class IV 4-5 ; 3-$ ° Clasg Y 3-0 2-4 4 I ' ! —-

" " 11 1 " Ill II I -I n - f "" Additional Sinking Fund Total Canital [Standard of Road and >r Cost Interest ch arges based on Total Capital Cost ™ s P for allowable Gross Weight. rennired per Mlle ' wr Mile a ? .? lg T^? rS 30,219 Miles, Miles, required F Ci Life per Mile. per Mile. ' * ' I | Unclassified (10 tons) .. 4 | 0 24 50-2 I'fifS'ooo Class II (8 tons) .. 720 j 360 18 37-6 10,875 000 M83,000 Class III (6| tons) .. 480 240 12 25-1 1 '122,000 Class IV (4f tons) .. 240 120 : 6 12-5 3,625,000 561,000 Class V (3 tons) .. . • • • | - i I

Class II. Class III. j Class IV. Class V. Total. Miles. ' Miles. I Miles. Miles. Miles. North Island 1,084- i 3,183 5,801 j 2,585 12,653 South Island .. .. 1,093 , 3,102 1,936 325 6,466 Totals .. 2J77 6,285 . j 7,737 . j 2,910 19,109. 1 '