When people think of "urban planning" their minds often jump immediately to large-scale infrastructure changes or totally designed cities built from the ground

When people think of "urban planning" their minds often jump immediately to large-scale infrastructure changes or totally designed cities built from the ground up, but it's exactly these sorts of little things that are actually the most important. Yielding to pedestrians, like you said, is an element of infrastructure, and it's cheap as hell to change attitudes about it. Parking is absurd. Planning codes have mandated numbers of parking spaces for businesses, so if you want to develop land your only option is to turn it into a strip mall. LA is an asphalt hellscape precisely because of this, parking requirements have made it so there is over 4.2 square meters of asphalt PER PERSON, just for parking alone. I only own a bike but live with a partner who has a car and I know it would be difficult to go completely without in my city (~300,000 pop.) I, like many people my age, am planning on moving to a larger more urban city that will have more public transportation and bike infrastructure, but I recognize that this isn't really the answer. Comparatively poor American millennials and gen-Z's that continue condensing populations into urban centers leaves even less incentive for long term change in mid-sized towns.