The increased tire load of super single tires or singled-out duals increases rutting in asphalt pavements and reduces fatigue life for all pavements. FHWAs Accelerated Loading Facility recently conducted tests on asphalt pavements which indicate that a super single tire causes twice the rutting and reduces the fatigue life by four times compared to dual tires under the same loading conditions. The effects of singled-out duals are expected to be even worse.
Factual data is not available to illustrate the extent which increased tire loading trend has developed or will continue to develop in South Dakota; nor is factual data available showing the extent to which South Dakotas highways are being impacted or will continue to be impacted by these trends. Research is needed to generate this factual data and quantify the extent which South Dakotas highways will be impacted.