H.—4o.

(ii) Classification of Main Highways.

While a little over 50 per cent, of the total rural mileage of formed roads is classified, there is now 88 per cent, of the main highway system, which carries the greatest part of the traffic, classified in one or other of the four classes, and nearly 82 per cent, in Class 111 or lower. As the classification of a main highway or other key road has the effect of limiting loads also on the adjacent feeder roads, the load-limitations virtually cover a much greater proportion than 50 per cent, of the total rural mileage actually classified. In order to provide a reasonable degree of flexibility for road transport it is most desirable that there should be a uniform classification over a large area of country, unbroken by variations at county boundaries. Since its inception the Department has advocated and encouraged the general adoption of Class 111 as the maximum limit for all rural highways, except where such highways are surfaced with the higher types of pavement, or where special circumstances justify heavier loads, and this policy has been adopted by a steadily increasing number of local authorities. In certain areas Class IV has been generally adopted as a maximum, as, for example, in the North Auckland District, where road surfaces are comparatively weak, and also in the pumice areas of the North Island, where surfacing materials are costly. However, in several districts, and notably in Canterbury, there is as yet no uniform system of classification. The following table indicates to some extent this lack of uniformity of classification of main highways in certain of the highways districts, and also sets out the relation between the classification of the roads and the use of the respective classes by heavy-motor traffic : —

The proportions which require a higher classification than Class 111 are seen to be relatively small in most districts, and there seems no reason why this class should not be adopted generally as the maximum in rural areas. In the course of time as the heavier vehicles now on the roads complete their useful life they may be replaced with the multi-axled type which on a Class 111 road has a maximum allowable gross load of 10 tons.

15

TT-^ ain Class II. Class III. Class IV. Class V. Highways. ncation. Miles. Miles. Miles. Miles. Miles. Miles. North Island 6,447 199 2,618 2,894 412 6,123 South Island 5,202 559 3,428 152 32 4,171 Totals .. ■■ 11,649 758 6,046 3,046 444 10,294

Classification of Heavy Motor-vehicle Classification of Main Highways. Traffic' „ . „ Proportions conforming to the following Highways District. Total Road-classification =- (a) Unclassi- (6) c!assified (c) Classified (o) Unclassi- classified (c) Classified fiedorm ' n T TT m Classes fied or in \' t T T m Classes Class II. m Class 111. IV or V. Class II. m Class Lll. IV or y. Per Cent. Per Cent. Per Cent. Per Cent. Per Cent. Per Cent. Auckland North .. .. 0-4 99-6 0-7 20-0 79-3 Auckland South .. 3-2 26-7 70-1 4-4 43-0 52-6 Tauranga .. .. 5-5 10-0 84-5 4-8 31-2 64-0 Gisborne .. .. 1*6 87 "5 10'9 3*8 45 • 8 50 • 4 Napier .. .. 12-4 81-3 6-3 9-4 41-2 49-4 King-country.. .. 6-4 .. 93 • 6 0-5 33-2 66-3 Taranaki .. .. 10-9 65*0 24-1 8 - 7 47•4 43-9 Wanganui .. .. 9-5 70-1 20-4 9-8 40-5 49-7 Wellington West .. 32-0 57-1 10-9 13-2 48-1 38-7 Wellington East .. 12-9 86-9 0-2 7-5 36-6 55-9 North Island .. 8-1 40-6 51-3 6-0 38-6 55-4 Nelson .. .. 12 • 6 78*1 9 - 3 12-5 31-2 56-3 West Coast .. .. 11-7 79-3 9-0 7-5 43-5 49-0 Canterbury North .. 43-6 49-7 6-7 14-0 34-2 51-8 Canterbury Central .. 79-6 18-9 1-5 12-5 40-2 47-3 Canterbury South .. 39-8 60-2 .. 6-2 45-3 48-5 Otago Central .. 33-2 61-4 5-4 3-8 38-5 57-7 Otago South .. .. 28-6 71-4 .. 4-4 42-1 53-5 Southland .. .. 0-9 99-1 .. 6-9 53-1 40-0 South Island .. 30-6 65-9 3-5 8-3 42-1 49-6 New Zealand .. 18-1 51-9 30-0 6-8 39-8 53-4