Arlington Bike Counts, Activity MapperArlington has a collection of automated trail counters which can distinguish between pedestrians and bikes, and can also record the direction of travel. This data is transmitted live to a database, managed with Eco Counter software. I recently got access to the data and was able to experiment with how to visualize it. I decided to add it as a dataset to my new Activity Mapper, which lets you animate and interact with a chronological and geographical data set.

For each coordinate, Activity Mapper lets you compare two numbers. For Metro it was entrances and exits at each station. For Capital Bikeshare it was bikeins and bikeouts at each station, and grew to include datasets comparing casual riders to registered riders, and trips that fell within or beyond the 30-min time limit. For my first look at Arlington’s trail counters, I chose to look at the past year of bike traffic (excluding pedestrian traffic), broken down into 365 days. The two data sets compare “trips in” to “trips out,” refering to the direction of the bike. Unfortunately, this version does not yet indicate the direction in the display.

The geographic layout is challenging because a few of the counters are clustered, and aren’t identifiable as distinct counters until you zoom in (by clicking on the spot). But it’s better than a strict tabular display, such as this earlier attempt to display Bicycle & Pedestrian Counts per Hour on Wed, Apr 10, 2013. I am displaying only 13 of Arlington’s trail counters. They have others that can’t distinguish between bikes and peds, or directions.

Here is a photo of one of the “double diamond” loop detectors, from the west sidewalk of Key Bridge. The post on the left conceals the battery, computer, and modem.

The map shows limited features: only the Potomac River and major bike trails are shown (the Custis trail, the W&OD trail, and the Mt Vernon trail).

To make it easier to discern patterns, I added a chart option, via a drop-down menu in the control section on top. The chart’s design varies depending on whether you are looking at cumulative data or segments, and whether you are looking at imbalances or not. For the bike-counter data, an “imbalance” is the difference between the two directions of traffic.

You can jump directly to the new data set by adding ?system=arlbike to the URL. What features would make this more useful? Which data sets would be interesting to play with?

Arlington Bike Counts, Mapped

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