Yest there are, in many states. Even in Texas you can't carry a handgun openly. You can carry a long gun, but not a handgun.
It's only recently that you could carry a handgun, concealed in your vehicle, without a permit/license. When I first moved to Texas in '77, you could not carry a loaded handgun at all. Even an unloaded one had to be locked away your trunk or otherwise be out of reach, and that was only changed, in series of changes to the law, over the past few years.
Worse, I suppose, would be to try to fire your cellphone at a perp.