I live in one of the poorest neighborhoods on the outskirts of my US city. There are a few major roads headed toward the more affluent neighborhoods and downtown. What I see when I run along/across or drive along those roads is mostly through-traffic. There aren't a lot of "shops" in my neighborhood, but one or two strip-malls and a few gas-stations and fast-food "restaurants".

Anecdata: In my experience, the areas with less through-traffic (and thus high-danger traffic) are areas with destinations, whether they're shops for goods and/or services or restaurants (that don't involve cars). The reason I think it's economic is because it's not just about the customers/consumers visiting these areas, but the workers. I'd bet that a not-insignificant number of workers in my neighborhood drive to another neighborhood for work, but the inverse is probably not true (that a lot of folks from other neighborhoods drive here for work).

I think part of the solution is to make communities smaller and more friendly to their inhabitants. There should be opportunities for work in these poorer neighborhoods, and that means the services to support them.

It doesn't matter what number is on the speed limit sign on these major roads, people will drive 50 anyway (I have been passed in the turn lane several times because I drive the speed limit on a 2-lane (one each direction) + turn-lane road).