Intersections are designed for motor vehicles, and although designs for safe crosswalks can be integrated, they don't reliably manage the hazards of turning vehicles. Left turning motorists are focused mainly on on-coming traffic, while right turning motorists are often looking the wrong way. Mid-block signaled intersections are a solution to this. Eliminating the right-on-red laws would be another step in the right direction.
A quick glance at available stats show Oregon have reduced pedestrian fatalities in recent years so perhaps the signs had something to do with it.