Money is speech. If there is no real ongoing problem with traffic flow, this is just a way to neaten up the sidewalks of the good citizens of Springfield. A guy under a bridge has just as much right to advertise for money as does a Presidential candidate. 
Having said that, I do think that it is normally not good to give money to people flying signs. I spent years homeless and saw that change almost always happened from the good work of social service agencies. If I have money to give, I give to them.
The way to get rid of desperately poor people is to spend serious tax money on emergency shelters, HUD long term housing, and programs like the recent local one that worked to end Veteran homelessness. Lane County has no public emergency shelters, none, in an area the size of Connecticut. When your company moves to Mexico, and tells you to shut up when you express your dismay, well, how would you survive? 


Hugh Massengill, Eugene