Vehicles can only cross the Potomac in 11 places, and the three that are for rail carry 30% of commuters across the river. It takes 57 highway lanes to carry the rest.

Photo by Scott Ableman on Flickr.

Virginia’s Department of Transportation recently looked at the current and projected volume at each crossing, then PlanItMetro analyzed the data.

Graphic by PlanItMetro. Click for larger version.

The six rail tracks carry nearly one third of the traffic, yet take up significantly less space.

The big takeaway, according to representatives from both VDOT and WMATA, is that any expansion of our region’s bridges should account for and include more than just cars.

One of VDOT’s recommendations is to continue the 495 Express Lanes from Virginia into Maryland by expanding the Legion Bridge. Should this happen, the region will be challenged to think proactively about how to integrate transit options; that goes for both what we have today and what we might have in the future. Adding a bus rapid transit route to the bridge, for example, could increase capacity by 14,000 crossings.

Graphic by PlanItMetro. Click for larger version.

Do we need to expand our bridges? Are the capacity improvements realistic, and if they are, are they worth the cost? Are there better solutions to get people across the river quickly and safely?

Correction: The original headline for this post read “Far more people cross the Potomac in trains than in cars,” which is inaccurate. What we meant to say was that proportionately, more people cross in trains than in cars.

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Katie Gerbes is a recent graduate of the University of Maryland, where she obtained her Masters in Community Planning. Her interests are largely focused around urban design and community development. Originally from Baltimore, she currently lives in downtown Silver Spring.