On one hand, it's kind of a tautology - sure, if you're in a city that is very car-dependent, it's a disadvantage to the working poor because owning a car costs money.
But in the US there are also (usually older) cities with relatively great public transportation that are more walkable that also have enormous amounts of wealth inequality.
Doesn't really have anything to do with inequality, in the US at least it's mostly just reflective of when cities were built and developed. Pre-WWII cities like NYC and Boston have (again, relatively) great public transit options and huge walkable parts, while newer cities (often in the South) developed around the car.