Couple of questions.
How do hovers brake? One of the major reasons boats need so much distance between each other, and larger craft literally consider "on the visible horizon" danger close, is because ships don't have any brakes and cannot stop (save dropping an anchor or letting water's feeble friction stop them over several miles) once they get going. Cars can maneuver closely together because they use friction from their tires to stop, unless hovers have a similar mechanic they're useless for land transport. This is the same reason hovercraft aren't used much on land today, they've capable enough of traversing land but can't stop fast enough to be safe for transport anywhere but on water where you have acres of space (steep hills are also an issue).
How does antigravity keep things off the ground? Does it stay a set distance from the surface, or perhaps a set distance from the center of gravity for the planet? The second option means car travel is out since the ground isn't perfectly level but antigrav technology would be extremely useful for, f'rex, machining as certain operations are limited by vibrations transmitted from the ground, and floating them in midair would reduce that.
If hovering is a certain distance above the surface how high are the limits of that? It might be a more suitable replacement for air travel or elevated trains than for automobiles.
