I suggest that the City of Seattle work with a non-profit [and seek federal funding] to retrofit arterials like Delridge Ave SW with rainwater-and-oil filtering parking areas.
Cars would park on top of rough-surfaced, water-permeable, plantable concrete pavers located immediately to the right and left of the lanes used by drivers. Bicycle lanes would be located between the parking area and the sidewalk, so that parked cars protected bicycle riders from fast-moving cars. This type of project would "calm" traffic and create a bigger safety buffer between the housing located along major arterials like Delridge - and the arterials, themselves. Unlike many economic stimulus projects, this project would rely less on heavy construction equipment and more on relatively unskilled labor. Having said that, laborers could be educated about plant filtration (horticulture), pollution measurement(chemistry), and civil engineering. The non-profit could start work in Seattle, but expand to other cities and states.