If black teenagers in Southeast DC are throwing stones at buses, endangering lives and causing property damage, the obvious solution is a police campaign to arrest some them, and put them in jail, possibly with "exemplary sentencing".
The DC government's alternative solution is pictured below: a poster asking them to stop.[See Don’t throw stones at glass houses—Residents of 97% Black Southeast Washington D.C. Warned About Throwing Rocks at Buses , by Paul Kersey, January 9, 2013]
This reminds me of the story that when Woody Allen was having a problem with pigeons on his New York balcony, one thing he tried was a sign saying "No pigeons."