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ROADS 4. Limitation of Loads on Roads. —In order to protect the road surfaces from the damaging effect of unduly heavy wheel loads, most of the rural highways and county roads have been classified in Class Three, Four, or Five, according to the standard of construction. Class Three allows of a maximum axle load of tons in the case of a two-axled heavy motor-vehicle, or 5 tons in the case of a multi-axled vehicle or trailer. Class Four permits of 4 tons and tons maximum axle loads respectively, and Class Five of 3 tons and tons. The following tables show the mileages classified at the present time :

(a) Classification of All Rural Roads at 31st March, 1946

(b) Classification of Main Highways (Rural Sections) at 31st March, 1946

(c) Classification of State Highways (Rural Sections) at 31st March, 1946

While a considerable mileage of the total length of formed roads remains unclassified, loading on much of this length is virtually restricted because of the classification of the key roads in each district. In the vicinity of the larger industrial centres the roads are usually of a high type of construction and capable of carrying heavier loads than the flexible-surface types of road which are generally adequate within a purely rural district. These high types (usually bituminous or Portland cement concrete surfaces) are thus not classified. Although it is usually desirable to limit loads on the flexible-surface types of road to protect the surfaces, consideration is also necessary of the effect upon road transport of restricting axle loads and thus payloads ; a balance must be maintained between the need on the one hand for preserving road surfaces, and on the other for facilitating economic transport.

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* Total Formed Roads. Class Three. Class Four. Class Five. Total Classification. North Island South Island Totals Miles. 26,817 22,232 Miles. 5,692 6,651 Miles. 10,288 2,612 Miles. 1,813 275 Miles. 17,793 9,538 49,049 12,343 12,900 2,088 27,331

(This section includes State highways shown under Table (c) following) Main Class Class Class Total Highways, j Three. Four. Five. Classification, Miles. Miles. Miles. Miles. Miles. North Island .. .. 6,680 3,213 3,072 167 6,452 South Island .. .. 5,424 4,577 133 42 4,752 Totals 12,104 7,790 3,205 209 11,204

— State Highways. Class Three. Class Four. Class Five. Total Classification. North Island South Island Miles. 2,112 1,686 Miles. 1,262 1,589 Miles. 799 Miles. Miles. 2,061 1,589 Totals 3,798 2,851 799 3,650