045-I Wyo. Code R. § 1.2
(1) The basics of spot speed data collection, such as site selection, sample size requirements, and the selection of target vehicles are described in the ITE Manual of Transportation Engineering Studies. For most spot speed studies used in Wyoming, vehicle speeds should be measured using automated methods such as radar or laser speed detection. The individual vehicle selection method is the preferred method of obtaining free flow speeds, with sample sizes of at least 50 and preferably 100 vehicles per direction being considered representative samples. The lower sample size can be used on lower volume (i.e., having two-way traffic volumes of less than 1,000 vehicles per day) roadways where the time to collect 100 samples per direction could be excessive.
(2) The data analysis required to make the final recommendations on setting proper speed limits can be conducted by professional engineers only. Those professional engineers are not required to visit the actual location where the study is being conducted as long as the required data was collected by trained technicians or engineers.
045-I Wyo. Code R. § 1.2