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What Kind of Count?

As explained in the Traffic Monitoring Guide, there are two types of counts: counts at an intersection and counts along a road or path segment. Counts at intersections often include turning movements.  Counts along a road segment are also known as screenline counts because any bicyclist or pedestrian who crosses an imaginary line drawn perpendicularly across the segment should be counted. The illustrations below depict these two types of counts.







Intersection Counts with Turning Movements



Segment Counts (also known as “Screenline” counts) 
 

Turning movement counts at intersections are typically collected for signal timing efforts and are desirable for traffic impact studies and safety studies. The complexity of counting multiple directions at one time usually requires more staff and/or volunteer time than segment counts and can compromise data quality if volunteers or staff are not adequately trained or if the counting task it too demanding for a single person. Additionally, Turning Movement Counts are much more difficult or expensive to collect using currently available off-the-shelf automated technologies. 

If automated counting technologies are to be used, segment counts are usually the preferred option, unless the automated counting technology used is contained in the signal detection equipment.1   

While automated counts have many advantages in terms of reducing budget per hour spent of counting and allowing much longer time periods for data collection, manual counts also have advantages in terms of raising community awareness of cycling and walking through volunteer count programs and allowing additional data such as gender or helmet use to be collected.

Resources

Multiple smart phone apps are available for counting bicyclists and pedestrians including Bike And Walk and Bike Count.

Kothuri and others describe how pedestrian activity and bicycle volume data can be collected using existing signal detection equipment.

 


GUIDANCE FROM THE TRAFFIC MONITORING GUIDE 2013, SECTION 4.5.2
4.5.2    SCREENLINE VERSUS INTERSECTION COUNTS

The two basic location types for non-motorized traffic monitoring are:

1.    Screen line counts that are taken at a mid-segment location along a non-motorized facility (e.g., sidewalk, bike lane, cycle track, shared use path); and,
2.    Intersection crossing counts that are taken where a non-motorized facility crosses another facility of interest.

Screen line counts are typically used to identify general use trends along a facility, and are analogous to most short duration motorized traffic counts. Although taken at a specific location, screen line counts are sometimes applied to the full segment length to calculate vehicle-miles of travel, pedestrian-miles of travel, and bicyclist-miles of travel.

Intersection crossing counts are typically used for safety and/or operational purposes, and are most analogous to motorized intersection turning movement counts. Example applications include using intersection counts to determine exposure rates at high collision crossings, as well as to retime or reconfigure traffic signal phasing. Intersection counts are typically more complicated than screen line counts and may require additional counters, primarily because multiple intersection approaches are being counted at once.

The uses of the non-motorized traffic data will dictate which types of counts are most appropriate.


1Kothuri, S. M., T. Reynolds, et al. (2012). Preliminary Development of Methods to Automatically Gather Bicycle Counts and Pedestrian Delay at Signalized Intersections. 91st Annual Meeting of the Transportation Research Board. Washington, DC, National Academies.