D.—l.

Classification op Roads relative to Maximum Geoss Loading. In September, 1937, the Commissioner of Transport convened a meeting of representatives of roading authorities and of commercial transport interests for the purpose of discussing the question of road classification in relation to pay-loads for the transport of general goods. Representations had been made to the Government regarding difficulties being encountered in providing for economic loads and at the same time affording an adequate measure of protection to the roads. A further aspect was the desirability of encouraging the most efficient and economic type of vehicle, having regard to its effect upon the road and its load-carrying capacity. The Board was represented at the Conference. General agreement was reached in the matter of maximum gross loading on Class V and Class IV roads, and it was decided to recommend an increase of one half of a ton in each class, making the maximum 3J tons and 5 tons gross respectively. With regard to multi-axled vehicles, the Conference decided to recommend the elimination of the existing gross weight restrictions and the adoption of certain maximum axle-loads for the respective classes. In the matter of raising the loading for Class 111 roads, the Board was unable to support the proposal to apply the extra half-ton to this class. No objection was raised to the increase for Classes V and IV for the principal reason that the general highways policy was to raise the standard of main highways to the existing Class 111 loading, and any cost involved in strengthening roads to that standard was regarded as part of the normal improvement programme. Furthermore, the additional half-ton on the lower class roads would allow of economic pay-loads to the advantage of transport and the country as a whole. It was considered that the time was not opportune for allowing extra weights on Class 111 roads, principally because the majority of rural main highways were not sufficiently developed. Eventually the proposed increased loading was sanctioned. The Conference also agreed to recommend that all goods vehicles exceeding 2 tons gross weight should be restricted to a maximum speed of 25 miles per hour. Testing op Highway Materials. As in former years, the Petrological Laboratory has continued the usual testing of rocks and metals, but it had been realized for some time that the standard tests for abrasion, hardness, and toughness were not entirely adequate to disclose the suitability or otherwise of metal and gravel for present-day roading. Some suitable tests for sealing chips crushed from water-worn gravel were also urgently required. A certain degree of success had been achieved in this direction by various loadings of the Deval abrasion machine, but it appeared that the Los Angeles abrasion machine, which has been successfully used in America and Australia, would adequately disclose the suitability or otherwise of road-metal and sealing-chips, whether water-worn or not. In this machine the stone is subjected to impact, so that the test resembles much more closely actual road conditions. A Los Angeles abrasion machine has been ordered, and should be in service for the approaching sealing season. During the year arrangements were made for the Public Works Office in Wellington to undertake the necessary testing of top-course aggregates, subgrade materials, and sealing-chips. Many gravels, rocks, sands, clays, subgrade soils, and sealing-chips have been examined and reported upon. Full advantage is being taken by many districts of this testing service, although some other districts do much of the essential testing-work in their own offices, and forward occasional samples for check tests only. The examination and classification of road-surfacing materials has become an important function of the Board, and gratifying results are being achieved in road-construction as a result of the testing-work. As roading authorities become more conversant with the advances that have been developed in subgrade practice, and as the value of the stabilized top-course becomes more generally appreciated, soil and gravel testing will assume even greater importance. The Dominion Analyst has examined and tested, on behalf of the Board, numerous bituminous materials for road surfacing. Owing to the shortage of certain tar products and asphaltic materials during the past season, the Dominion Analyst was often called upon to make the necessary tests and to suggest suitable mixtures to take the place of bituminous materials which were not available in the country. As yet very little research work has been undertaken in connection with bituminous materials for New Zealand roading, but the time is opportune when some investigation, apart from routine testing, should be carried out as to the most suitable materials for the conditions obtaining in this country, and for the types of work developed by the Board. For instance, viscosity-temperature curves for road oils would be most valuable, as also would curves of viscosity or ductility plotted against age or period of service. This latter test would require the development of some form of accelerated weathering. Highway Engineering and Design. The continually increasing volume of motor traffic over the past few years and the highwayaccident rate have shown that existing standards of road design in New Zealand will not meet the requirements of future traffic. This is a world - wide problem which is being attacked no less energetically in New Zealand than in any other motoring country of the world. Research has been concentrated on the geometrical layout of the road and the building of the greatest measure of safety into the road surface itself. The difficulties to be faced will be appreciated when it is realized that, owing to the comparatively short life of a motor-vehicle, it can be redesigned and improved every few years, whereas it would be quite out of the question to redesign our roading system even, say, every ten years. However, against

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