For streetcars to move through traffic, rail tracks have to be free of parked cars. To keep them that way, the rules of the road must be crystal clear for drivers.

Streetcar parking zone sign, Seattle.

Last week DDOT used a truck for a test-run of the H Street streetcar route, and because of illegally parked cars, the going was slow. But other cities with similar streetcar layouts, like Seattle and Portland, have had a lot of success keeping their lanes clear. How do they do it?

With constant and clear communication to drivers, like the sign pictured here, and with strong enforcement.

Any time you take pavement away from cars, there’s a learning curve. Drivers accustomed to doing as they please have to change behavior. That’s to be expected, and it doesn’t happen on the first day you run your first test truck. But most drivers do fall in line, once they understand what’s changed. That’s how streetcars have worked in other cities.

And if all else fails, ticketing cameras mounted on streetcars, like in San Francisco, would solve any remaining problem in a hurry.

 Cross-posted at Greater Greater Washington.