People being struck walking alongside a country road require a different solution than someone crossing a lane mid-block at night in an urban area.

If the rise in deaths is mostly people crossing the street away from crosswalks in urban areas, building sidewalks alongside rural roads won't solve much.

The person that you are replying to could have certainly phrased it better if my interpretation is what they were really asking.

What variable are we trying to understand? Probably ones that we can influence through car safety, lighting improvements, crosswalk design, barriers between cars and pedestrians. But if the exploding homeless population are stumbling around drunk, it’s going to obscure the data on the above improvements.

drug or mental impairment