You can have both, if you have a grid of main through-roads for transporting people around and then inside each "square" of the grid you have a continued fractal of sub-grids which aren't for through-traffic (slower speed limits, narrower streets, traffic calming measures, difference in material to make clear the difference from through-roads and local streets etc.). People traveling past won't use the inner streets because they aren't efficient for that, but people living in the neighbourhood will use the inner streets.