A recent Data Visualization Hack Day not only drew coders from around the region, but also some WMATA planning staff. They used a Javascript library to build a calendar of Metrorail ridership, showing each day’s ridership since 2004 as a square of a different color.

Image by WMATA. Click to enlarge.

If you go to the large and interactive version on PlanItMetro, you can mouse over individual squares to see the date as a tooltip.

The darkest red days have the lowest ridership, the darkest green the highest. You can see high ridership events like President Obama’s January 2005 2009 inauguration, the Stewart/Colbert rally in October 2010, Snowmageddon/Snowpocalypse in February 2010, and more.

Stepping back, it’s clear how ridership is highest in April, June, and July, and the number of very high ridership days jumped significantly in 2008 but then has stayed flat or a bit down since. Weekend ridership has gotten lower in recent years, probably because of all the trackwork.

What do you notice?

David Alpert is Founder and President of Greater Greater Washington and Executive Director of DC Sustainable Transportation (DCST). He worked as a Product Manager for Google for six years and has lived in the Boston, San Francisco, and New York metro areas in addition to Washington, DC. He lives with his wife and two children in Dupont Circle. Unless otherwise noted, opinions in his GGWash posts are his and not the official views of GGWash or DCST.