Hi everyone,
In case you haven't come across these yet, here are a couple of potentially helpful reports from the FHWA released in 2016:
Bicycle-Pedestrian Count Technology Pilot Project https://www.fhwa.dot.gov/environment/bicycle_pedestrian/countpilot/summary_report/fhwahep17012.pdf which compares different types of counters and lessons learned
Guidebook for Developing Pedestrian & Bicycle Performance Measures https://www.fhwa.dot.gov/environment/bicycle_pedestrian/publications/performance_measures_guidebook/pm_guidebook.pdf including a toolbox for different contexts (see Chapter 4)
(additional resources https://www.fhwa.dot.gov/environment/transportation_alternatives/performance_management/ to Guidebook above including webinar recording and slides)
cheers, Beth