The dusty roads of Southern California made it necessary to find a means by which the dust might be effectually laid without too great an expense. Water was scarce and the cost a great deal, so that process had to be abandoned, at least to some extent.
In the spring and summer of 1898, six miles of highways were oiled by Los Angeles County and in 1899 the same roads, with an additional seven miles were oiled. This experiment proved to be very satisfactory and in 1900 fifty miles were oiled, most of this being oiled twice.
The process, as now in use, took some time and experimenting to perfect. At first oil was sprinkled on top of the road, just as water is used. Although this laid the dust, to some extent, yet it was not very satisfactory, because the oily particles, flying around in the air, stuck to everything they came in contact with and left grease spots on the clothes. The best and most used process of today consists of first plowing up the road to the depth of about one foot. The clods are then broken up if not too large by harrowing, but sometimes sledge hammers and mallets must be used. After the soil is thoroughly pulverized, a road grader is used to make the road even, and shape it so that it will shed water. After being again harrowed and rolled crude oil is sprinkled over it, after being heated to a temperature of from one hundred and seventy to three hundred degrees Fahrenheit. From one hundred twenty to three hundred barrels' per mile, depending on the width of the road, are used. If the road has very heavy traffic, sometimes as many as four hundred barrels per mile are used. In a few weeks, a second coating is applied and then coarse gravel or sand, usually river sand is the best, is sprinkled over the top to absorb the surplus oil. After the road has been used a few weeks, it becomes as solid as macadam, the oil having mixed with the fine soil and thus forming a solid mass. The color of the road is from dark brown to black. The oil has little or no effect on rubber and does not hurt rubbed-tired vehicles to any extent. After a few weeks no oil stains are left on the tires and the dust is effectually laid for one and sometimes two years.
California oil contains mostly asphaltum and petrolene. The asphaltum being hard and brittle forms part of the road and the petrolene absorbs the dust. About one thousand miles of oiled roads have been completed in California and the oil costing from sixty-five cents to one dollar per barrel. In Golden Gate Park in San Francisco, four and one-half miles of a thirty-five foot road were oiled at a cost of one dollar per barrel applied and six thousand barrels were used. The road was much better than before and the Park Commissioners estimated that about five hundred dollars per month and seventy thousand gallons of water per day were saved.
Many private corporations are using oiled roads and they are especially valuable in parks and cemeteries because there is not only a lack of dust, but also a lack of weeds. The roads also dry off very quickly and there is never any mud to be seen.
From the publication:
AACS - Proceedings of the 21st Annual Convention
Held at Providence and Newport, RI
August 20, 21 and 22, 1907