Transportation departments across the United States have installed sensors mounted on towers by the roadside to measure road surface temperatures. Since no guidelines exist for verifying the accuracy of such measurements, agencies are forced to accept claims made by vendors. To correct this situation, the Idaho Transportation Department (ITD) contracted with Boise State University (BSU) to test the accuracy of the non-contact, infrared temperature sensors installed throughout Idaho. Before collecting independent temperature data, BSU devised an easy-to-use procedure for determining the effective area viewed by the infrared sensors. According to ITD, the vendor claimed that at a distance of 10 m between the sensor and the road surface, the diameter of the effective area viewed by the sensor would be 80 cm. BSU’s field experiment revealed that the sensor’s viewing area was much larger than that claimed by the vendor. The discrepancy suggests that other claims made by the vendor regarding the accuracy and precision of their measurements cannot be relied upon and transportation departments will need to conduct independent tests to verify such claims.
This document was originally published by International Association of Journals and Conferences in International Journal of Modern Engineering. Copyright restrictions may apply.
Khanal, M. and Davidson, R.. (2013). "Field Procedure for Estimating the Measurement Area of Non-Contact Temperature Sensors". International Journal of Modern Engineering, 14(1), 81-87.