Reinvent downtown streets by making them a bit narrower and use that space to plant desert friendly shade trees. The trees would provide respite from the brutal heat for pedestrians and create a barrier between cars and the sidewalk. Ultimately it could expand into areas with high pedestrian activity, like 7th ave to I-17 along Camelback and Glendale from 15th ave to the freeway. Those areas already have lots of pedestrians and would have more if people didn't have to walk inches from cars driving 50+mph.