DUSTLESS ROAD TO BE MADE

Southland Times, Issue 23438, 19 February 1938, Page 6

DUSTLESS ROAD TO BE MADE

Kennington-Dacre Highway f NEW METHOD OF OIL SURFACING

A method of road surfacing commonly practised in other countries and in the North Island, but quite new to Southland, will be begun by the Main Highways Board on Monday on the section of road from Kennington to Dacre. The road will be given a coating of tar next week and motorists are asked to co-operate with the Public Works Department by reducing their speed over the treated stretch to 15 or even five miles an hour.

By this new system disintegration of the road surface while consolidation is taking place is prevented. In addition a much more pleasing and dustless surface is provided for the motorist. The tar-oil treatment will cause the road to remain wet for some considerable time and motorists who do not exercise caution will run the risk of having their cars splashed with tar, besides causing damage to the surface. The Automobile Association (Southland) has received from the board the following information on the preliminary measures in sealing the road:— “As Invercargill motorists are no doubt aware the 10-mile section of State highway from Kennington to Dacre is being metalled arid prepared for bituminous surfacing. Although the Main Highways Board is anxious to provide a sealed road at the earliest possible date, this work cannot be undertaken until next season, because it will take many months to produce the big quantity of metal chips required for the construction of a seal coat. A DUSTLESS SURFACE “Although the wearing course of bitumen and metal chips is not possible this year, every endeavour is being made to provide a dustless road within the next month or two. The dustless surface will be obtained by an application of tar oil. “The tar oil treatment not only provides the motorist with a much more pleasing surface but it also prevents the heavy wear and loss of metal which normally occurs during the winter. It is by soaking into the hard metal surface and coating the individual particles that the tar oil prevents the formation of loose dust. As it is essential that most of the tar oil should completely penetrate and soak into the road, the tar must not be covered with any appreciable amount of metal chips or gravel. This means that the road surface may remain wet with tar oil for a few days after application. The attention of motorists is particularly called to this, so that they will reduce speed to a sufficient extent to prevent the splashing of their vehicles. “Oiling work should not be with ordinary sealing where the bitu-, men is immediately covered with peagravel or stone chips and then opened l to traffic.

“The oiled surface is. in no way intended to be a final wearing surface. The oil lays the dust and at the same time allows the foundation to compact) under the action of traffic. During) next spring or early summer those! areas of the oiled surface which have, ravelled or pot-holed will be lightly! scarified, reshaped and bitumen-sealed.

REDUCED MAINTENANCE COSTS “The maintenance of this particular highway with a gravelled surface until next summer would be much more expensive than the cost of the oil treatment, plus maintenance of the oiled surface, and furthermore the motorist would not have the benefits of a dustless road. The maintenance of the gravelled surface would require periodic applications of gravel and continuous grading whereas the oil work will require only occasional patching. To reduce maintenance costs and at the same time to provide the motorist with a dustless road at the earliest possible date, tar-oiling of gravelled surfaces is practised extensively in overseas countries and in many other districts of New Zealand, 1 but as such work is new to Southland this explanation is being made for the benefit of Invercargill road users. “To some extent sand and grit will be used to blot up wet tar oil but as this is detrimental to the road only the minimum of sanding can be done. While sections of the road remain wet with; oil motorists are requested in their own! interests to traverse that particular sec-; tion at speeds of 15 or even five miles; an hour where there is any tendency 1 for the oil to splash about. If oil roads) are negotiated at high speeds, vehicles) become splashed with tar oil and also 1 much damage is caused to the road surface.

’ “The department is anxious to cause motorists the minimum of inconvenience, but to make the road permanently better it must first be made worse for short periods. Most motorists are always quite ready to show consideration for the roading authorities and with this explanation of the position, it is hoped that all road-ussrs will give the Public Works Department and the contractors the fullest co-operation during oiling and future sealing operations.”