SCIENTIFIC ROADING.

Waikato Times, Volume 113, Issue 18878, 23 February 1933, Page 9

SCIENTIFIC ROADING.

REPORT TO OIVIL ENGINEERS. IMPORTANT RECOMMENDATIONS. Problems associated with the economic and scientWo aspects of roadlng are discussed in a report presented to the annual conference of the New Zealand Society of Engineers at Christchurch. Even with the expenditure of nearly £7,000,000 on rural roads in 1931-32 the improvements in general had not been extravagant or extensive, the report stated. Of the 11,000 miles of road declared main highways only 10GG miles had been surfaced with tar, bitumen or concrete, and many miles remained with an unprotected gravel surface, which could he econoincally surfaced with more durable materials. The first consideration of the road engineer In regard to road crust and surface conditions was the loading of vehicles, and in that respect a llmllaton of loading to Gi tons on four wheels was deemed to be the highest economical limit for New Zealand rural highways. The use of solid tyres was condemned on any hut the slowest-moving vehicles. An Important Feature. One of the main features of the report was the investigation into the question of difference in cost between operating motor vehicles on gravel roads and on Surfaced or dustless roads. It Is stated that for each 100

motor vehloles per day, of which 2® per oent. were motor trucks, the saving In operating oosts by adopting an Improved road surface of the dustless order amounted to not less than £127 per mile per year. The-surface whloh would give those results might be of a low-cost type consisting of a sealing coat of bitumen or tar. Good roads of the proper type were not a luxury demand, but were an economio i necessity under the existing conditions of traffic. For a traffic not in excess of 1000 motor vehicles per day, Including 20 per cent, of motor trucks not exceeding 64 tons gross weight, a bitumensealed surface on a gravel or macadam road crust 61n thick, under average New Zealand conditions, had undoubtedly been proved the best road. Road Finanoes. ! The report also dealt with the question of road finances and with the constant loss In road crust thickness on unprotected surfaces, which had been proceeding at a rate much in excess of present replacements until tha present loss was estimated by the Transport Department to amount to £5,000,000. Secured finances were advocated In the report. It was pointed out that the allocation of funds for road purposes was now made too late in the season to achieve the most economical results, and in this connection the Main Highways Board should be In a position to approve definitely of works a considerable time ahead so as to allow.the preparation of the surface and other incidental work .to be proceeded with in proper seasons,