SSI Certifies With North Carolina DOT
On May 20th an SSI CS9500 inertial profiler certified with NCDOT
With the introduction of engineering staff to South Carolina, SSI has certified an inertial profiler with the North Carolina Department of Transportation (NCDOT). The certification status informs agencies and contractors of the SSI’s local presence.
The NCDOT certification track near Durham, NC has two tracks, smooth and medium smooth. Although the certification closely follows the AASHTO r56 method and has SurPro reference profiles in each wheelpath, accuracy is determined with an IRI comparison. The repeatability threshold is still 92%. The smooth surface has IRI values near 70 in/mile while the medium-smooth surface has IRI values near 100 in/mile and 160 in/mile in the left and right wheelpaths, respectively.
The certification was also an opportunity to introduce NCDOT to SSI’s Zero-Speed upgrade. After the inertial profiler certification was complete, SSI collected additional runs on the smooth surface to prove that the Zero-Speed could be certified under the NCDOT certification requirements. During the Zero-Speed tests the SSI CS9500 Zero-Speed system stopped in the middle of the track, held its position for a moment, and continued to the end of the certification track. The repeatability of these Zero-Speed go-stop-go runs were 98% and 96.7% for the left and right wheelpaths, respectively.
