Is it normal to say hi to people you don't know?

Not at all. Its just being friendly

yes,Somtimes I am in the car and I wave,half of them wave back.

I only say hi if there is eye contact and a smile. Otherwise I assume they just want to be about their business just like the rest of us.

In the smaller towns I find it everywhere, in bigger towns people seems to ignore each other.

I do this a lot in the small town where I live, whether or not the person seems to be a local I haven't met yet or a visitor, unless the person is deliberately looking elsewhere so as not to be spoken to.

I agree...it's much more common down south or in the mid west.....in new England people act all creeped out if you do it.

I'm from ny and people aren't as friendly in ny as they are down south. People down south wave at you and speak to you, they are so much more friendly down there. So when I'm walking and I make eye contact with a person walking pass me here in ny now I will say good morning or hello. I feel good about myself when I speak to people.