Case study: performance effectiveness and cost-benefit analyses of open-graded friction course pavements in Tennessee

The effectiveness and cost-benefit of Open-Graded Friction Course (OGFC) pavements were analysed in this study by investigating the cost, field performance, short- and long-term effectiveness, and accident rate of OGFC projects in Tennessee. Paired sample t-tests were conducted to compare if there was significant difference between OGFC and non-OGFC sections. Investigation on the performance effectiveness showed that OGFC sections provided comparable performance level as traditional dense mix overlays and were effective in improving pavement performance and repairing deterioration except for rutting potential. However, no severe pavement deterioration was observed on the OGFC sections after more than four or five years of service, indicating sufficient durability of the OGFC used in Tennessee where mild freeze-thaw cycles are experienced annually. Although the unit cost ($/m(3)) of OGFC was about 42% higher than the cost of traditional dense mix overlays, it was observed that the accident rate was significantly reduced especially in rainy days after the OGFC treatment. The cost-benefit analyses based on the ratio of accident rate reduction over cost demonstrated that OGFC was significantly more cost-beneficial in improving driving safety and reducing accident rate in rainy days.