Evaluation of Trapezoidal Shaped Grooves

the differing sections of pavement type and surface treatment, including the areas with the standard and trapezoidal-shaped groove areas, are shown in figure 38.

Figure 38. The MCAF Quantico Friction Run 1R—Dry Pavement Excluding the data collected from the ungrooved pavement area in the middle section of the runway, the average friction value for the grooved areas for the first run, run 1R, was 0.72 mu. Shortly after this first run, light rain began to fall at the airport. The RFT continued collecting data on the wet pavement surface, and the self-contained wetting system still activated. The results of this run, titled run 4R, are shown in figure 39. The average measurement for the grooved areas of the runway was 0.70 mu. Approximately 25 minutes after this run, a significant thunderstorm occurred with heavy rain that reduced visibility at the airport down to near 0 ft. The Operations personnel suspended data collection temporarily until visibility improved. Approximately 5 minutes after the downpour subsided, data collection runs resumed. Figures 40 and 41 show data collected 5 (run 3L) and 10 minutes (run 4L), respectively, after the downpour

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