Developing on this - not to keep -cars- away as they're usually "suburbs" which would atrophy and collapse without the private auto. But to - keep -anyone who doesn't know the street layout- away. It's a method to make the locale less hospitable to outsiders. This pattern is also due to the fact that these individual subdivisions do not connect to a distributed grid but to a tree-like branching of streets from largest trunk (freeways) through to branches (thoroughfares) to twigs (local streets) to leaves (individual properties). The subdivisions themselves are the investment of a single real estate development entity, and created without the requirement to connect to the larger whole except in this tree-mimicing organization.

This is especially obvious in Southern California where they've been putting up "emergency access roads" that have automated gates that respond to IR flashes from emergency vehicles so commuters can't use the suburbs as through streets but emergency services can still drive through in case of fire or other emergency and pedestrians can walk through. They're required for developments that want to stay isolated.

One of those roads splits my neighborhood into two clear halves with each half only access by one artery, so that commuters don't go gunning through the neighborhood.

How do local residents drive in?

The main entrance/exit. It’s a bottle vs pipe situation.