"It's likely that without these billboards, Republican candidates will ignore systemic racism and discriminatory policing in next week's debate," Color of Change wrote in an email to its members asking for contributions to help fund the billboard purchase.
"No one will raise the fact that police kill Black Americans at nearly the same rate as Jim Crow era lynchings, and more than 175 Black people have been killed by police this year alone. But we cannot afford to allow this dangerous silence to continue.
"The billboards around the convention center will honor Tamir [Rice], Tanisha [Anderson] and John [Crawford III], while probing debate moderators to ask the questions we need answered."
Here's an image of all three local signs, designed by Lindsay Eyth:
On the other side of the political spectrum, Democratic candidate Bernie Sanders has taken a more direct approach:
Somewhat new in Bernie speech: Reciting the name of black people killed by police. Eric Garner, Michael Brown, etc.
— daveweigel (@daveweigel) August 2, 2015