Is it leagal for a cop to park in a drive way of a bank owned home to catch people speeing? Isn't the trespassing? If I parked there I would get in trouble!

He may have prior permission to park there. Did you ask him?

I asked him could I park there too and he got an attitude and said only if I had a raidar gun haha.

You didn't ask him if he had permission. You asked him if you could park there. Big difference.

Yes, he can park there as long as the owner of the property does not care.

If for example this is an empty property, they will be glad to have the police there often.

You could go to the owner of the property, and ask them to complain.

*** sounds like you got a ticket and don't like it.

Most likely the police department has a "letter of agency" on file authorizing the police to act as their agent in order to enforce things such as trespassing. So yes, he would be fully within his right to park in the driveway. Why do you think convenient stores give cops free coffee? It isn't just out of the kindness of their hearts. They realize they're less likely to get robbed if the police come in there often.