PennDOT's Traffic Counting video covers many aspects of setting counts in the field, with particular emphasis on safety. You can also download the video (500 MB) to save it for future reference.
Traffic Counting
Counting traffic volumes and vehicle types is important to ensuring the department and stakeholders have accurate data to use in decision making. These resources help traffic counters conduct these counts accurately and safely. See section 6.12 and 6.13 of the department's Traffic Engineering Manual (Pub 46) (PDF) for requirements for workers' attire and specialized operations.