Much light pollution would be eliminated merely be ensuring that lights do their job well. For example, the purpose of the flood lighting shown below is to protect property or provide visibility. But it does either of these poorly.

First, whether it protects the driveway or vehicles parked there from theft or vandalism is debatable (I have numerous examples of theft and vandalism occuring in the presence of flood lighting). And second, it creates enough glare to be a nuisance and safety hazard, which undermines its benefit. Note that the light is cast upward and outward as well as downward. Lighting the trees across the street provides no deterence to theft or vandalism, and is a waste of energy. But more relevent to a residential neighborhood with children, it creates glare that can impair a motorist's ability to see a rock in the street or a child on foot, on a skateboard, or on a bike. Cameras tolerate glare better than the human eye, so the following photos will show objects clearly, but use the next two photos in sequence to get an idea of how your vision would respond to the sudden appearance of the light from behind the tree.

Visibility is good here for both the camera and the eye, because the tree effectively sheilds the light. But as soon as you drive out of the shadow of the tree, the light is like a stab in the eyes.

At this point, the motorist's eyes are adapting to the brightest light -- the flood light. The pupils are contracting and the faint light from pedestrians is overwhelmed by the glare. This is similar to the approach of another car's headlights. The difference here it that lights like this become permanent fixtures, always interfering with seeing. I know of numerous intersections where left and right turns are hazardous because there is always an unshielded light in the way of the where I need to look to make a safe turn. The solution is simple. Shield the light with a viser so that it lights only the driveway and sidewalk. This shielding would allow the light to perform its function without the nuisance and hazard of glare, which in turn reduces light pollution.