See Chapter 4 of the 2013 FHWA Traffic Monitoring Guide
This is the first edition of the Traffic Monitoring Guide to include information on monitoring pedestrians, bicyclists, and other non-motorized road and trail users. Even though both of these modes preceded the automobile, the monitoring of non-motorized traffic has not been systematic or widespread in the U.S. and, even today, is not nearly as comprehensive as motorized traffic monitoring.
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