ROAD IMPROVEMENTS

Digger (Invercargill RSA), Issue 26, 10 September 1920, Page 13

ROAD IMPROVEMENTS

Town Engineer's Report

Engineer's Office, Invercargill, September 7, 1920. TO HIS WORSHIP THE MAYOR AND COUN CELLORS Gentlemen, — Acting on instructions from the Works Committee, I beg to submit the following report and estimates. of cost for improving the condition of a portion of the town streets, and the two arterial roadways leading into the town, work orendered necessary, owing to the change in the class di vehicle now in general use. The streets proposed to be improved and defined by the Works Committee are apart from the arterial roads situated within the town area between and including Gala and Wood streets and Leven and Deveron streets, also Tay street to the Eastern boundary of the Borough, and Dee street to the Waihopai Bridge. , In recommending the best form of construction to be adopted in connection with these streets, the difficulty encountered is to estimate what the future traffic conditions will be, more particularly in regard to axle loads. The rapid development that has taken place in the adoption of motor driven commercial vehicles, carrying heavy loads at high speeds, and with every prospect of these conditions being. increased, tends to complicate the roading problem, as a modern roadway at moderate cost, that will prove quite satisfactory under present conditions, will be a fairure if it has to witfetand the heavy vibrations that will be set up if the loading is increased. The experience in some towns has proved that an improvement in the thoroughfares has almost immediately resulted in a corresponding increase in the carrying capacity of motor waggons and vans, with the result that a further expenditure has been necessary to still further strengthen the roads to meet these new conditions of traffic. The correct metliod to adopt would, no doubt, be to construct the roadv -y of suf. fiicent strength to meet antieipated future conditions. Although this method may be adopted in cfties with a large revenue, it' is beyond the means of smaller communities and in preparing my estimates I have prov'ided for suhstantial construction on th'ose thoroughfares at present known to be subject to heavy traffic and varied the construction on other streets to meet present conditions. This principle may lead to heavier maintenance charges, but against this we have the comforts of a greater length of improved roadway, a reduction in the wear and tear on motor tyres, and the dust nuisance greatly reduced, than if only limited lengths of the more expensive construction are carried out. Regarding the annual charges which will have to he paid in connection with the cost of carrying out the works provided for in the estimate. It is safe to assume that within the next year or two all motor driven vehicles will he taxed, and that the revenue frorft this source will greatly assist in paying interest and other charges on the expenditure. Apart from this it is now generally admitted that the day of the water-bound macadam road is past, and some more permanent form of roadway must he constructed to meet the changed conditions of traffic ; and so long as the present class of roadway remains in existenoe so much longer will the country continue to send tens of thousands of pounds out of the country for motor tyres and snch like. The greater proportion of this sum could he saved to the community by providing more permanent roads, which would he a benefit to all fnstead as at present being a drain ©n the financial re- ' sources of the country. Regarding the proposed new construc-. tioft If it had not been for the fact that the Corporation own the tar, and, that there is a difficulty in disposing of it, I would have strongly recommended the adoption of one of the South Ajnerican natural hitumen products in place of tar. It has heen definitely proved by practical experience that hitumen used as a road binder provides a more satisfactoi-y road with a longer life, and less maintenance than can he obtained "with tar; particularly so in a wet climate, and, apart from this, bitumen, due to ita quiclt setting nature permits of a roadway being open-

ed for traffio immediately the new surface is laid without risk of damage. No provision is made in the estimates for dealing with the remaining fifty-one miles of streets in the Borough. But in regard to these I would advise that they he taken in their order, according to traffic they carry, and put in good repair during the autumn and winter months, and in the late spring, after rolling and bruising with liard brooms the surface to be tarred and sanded. In regard to surface tarring the success or otherwise of this form of road surface treatment depends entirely on the weather conditions. The roadway must be dry, and the weather fine for at least twentyfour hours after the tar is spread. A wet road in the first case, or rain too soon after laying the tar, it can he taken for granted ,that the work will not, De a success. Regarding future maintenance, provision must be made for tarring and sanding all tarred roadways every year, and not less than every other year, for tarred macadam surfaces. Regarding concrete roadways the maintenance on these will congist of a t-hin coating of bitumen^ and sand every second or tbird year, according to the amount of traffic the roadway carries ; but allowing for this, the annual charges under ^ this head will be considered lighter than on an ordinary water bound macadam road carrying the same class of traffic. I am, Yours faithfully, (Signed) G. F. CLAPCOTT, Town Engineer. IMPROVEMENTS OF STREETS. - ESTIMATES. TAR, MACADAM AND CONCRETE ON STREETS IN TOWN BLOCKS. — Tar Sprayed Roads. — Gala street, Leet street, Deveron street, £3,100. — Tar Macadam. — Yarrow street, Don street (3in tarred) ; Esk street, (macadam) ; Tay street, Crescent (Garpeting) ; Tay street shrdluuuu cent, Tay' street, Kelvin street, Dee street, Dee street, East Road (carpeting on existing road surface), £40,811. — Concrete and Tar Macadam.— Spey street (centre concrete, flanks macadam) ; Leven street (flanks macadam) ; North Road (flanks concrete), £23,167. — Heavy Bitumen Macadam. — Wood street, £2, 093. Contingencies five per cent. £3,458 10s. Total £72,629 10#. Estimated cost as per schedule £72,629 10s. Plant-, etc. £1,250; cost of r&ising loan £750; total cost £74,629 10s. Total cost say — £74,700; 1st year's interest and sinking fund 71 per cent. £5,602 10s. Total estimate £80,302 10s.