Diamonds are a Girl’s Best Friend

tim kelley cargo bike arlington count
Tim Kelley Tweet Us @BikeArlington@BikeArlington October 6, 2016

Tim Kelley is the former BikeArlington Operations Manager.

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Curious how trail counters actually count the number of bikers and pedestrians? Just look for the diamonds in the road - they're Arlington's hidden gems.

Michelle on a Bike

Like many reluctant bike riders, Michelle Cragle saw Metro’s Safetrack campaign as a welcome spur to get her to do what she knew was good for her. She started taking Capital Bikeshare from Rosslyn (where she formerly worked as a Director of goDCgo and shared an office with us at BikeArlington) to the East Falls Church Metro station to avoid the expected platform crowds. And in the early days of Surge One, the totals on some of Arlington’s automated counters jumped by as much as 90% over the same dates in 2015. So we thanked her for adding to the counts, and coached her to make sure she hits her marks to keep getting counted.

Hidden “gems” on the pavement

“But wait,” Michelle asked, “How do I know when I’m counted?”

“The best way,” we told her, “is to ride across the peaks of the diamonds.”

“What diamonds?”

“The diamonds that mark the counters in the ground,” we said.

And thus, Michelle was on a mission. She was going to find them. We explained that the sensors that pick-up the rolling metal of a bike (and then count it) are embedded in the asphalt of the streets and trails and can easily be identified by sets of diamonds. The sensor work best when you ride across the thickest/widest part. It’s possible to ride between the two at the narrowest point and not get counted.Bike Counters

Bike/Pedestrian documentation

Arlington has an extensive system of 34 counters, and can be viewed on our Bike/Ped Counter Dashboard, which now includes counters from DC, Alexandria and Montgomery County, MD. So finding them is not that hard. Check the map. Plan accordingly!

The counters can give us very granular data, like direction of riders, in 15 minute increments, and are also synced with weather data that tell us what the sweetest ride conditions are. Like in this analysis done by the Data Lens’ Kate Rabinwitz, literal heat maps can illustrate that low-humidity and mid-70s is about as good as it gets.

Michelle reported back to us with great excitement that she had found the counters on her commute, and now makes a point of rolling across the widest points of the diamonds, getting even more benefits besides the usual ones related to time, money, and physical health. Her brain now gets a shot of dopamine with each diamond rolled over, and with it a sense of calm and accomplishment, knowing that she aided our efforts to count people riding bikes and making the world a better place.

Do you have a great commuting story? We want to hear from you. Email

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