You’re right that a grid doesn’t necessarily = urban, but it is still one of the best indications of the potential for urban development. If you look at most cities, single family homes are often bought out and redeveloped into larger buildings as downtowns expands, and this is in large part driven by a continuous rectilinear grid. I was just in Toronto, so to use it as an example: if you look at the city’s graining, commercial areas line the E-W thoroughfares, and single-family neighborhoods fill the blocks in between them. The density trickles into the residential neighborhoods via urban infill, which makes for a walkable city that extends far beyond downtown. From my (limited) understanding, this is urban planning 101 – a robust urban grid is the framework for a pedestrian-oriented city (including walkability and efficient public transit), while meandering, sparser streets are built for the car and usually lead to suburban sprawl.
Which cities are you thinking of? The only thing that comes to mind for me are the historical inner cities that can be found all over the world, but that kind of density isn’t realistic for Raleigh. I’m wondering if there are any good examples of turning around this kind of suburban sprawl in cities that are built similarly to Raleigh?