[dymk]

What are these low speed roads you're talking about? I'm not aware of any laws that allow a car to not have airbags on public roads based on speed.

The closest thing I can think of is e.g. communities that have dedicated paved roads (which don't allow normal cars) for golf carts to putt around.

[crooked-v]

You seem to be unaware that low-speed vehicles (https://en.wikipedia.org/wiki/Low-speed_vehicle) exist as a legal category.