I need an RFID tag that can be read from a distance (like say across a street). I plan on it having its own battery power however to save battery I only want it to transmit to my receiver when it detects a signal.

Lets say my receiving station constantly puts out a signal. Is there a way that I could only have my RFID tag send a signal back when it gets the received signal but completely turn itself off (use no battery power) when not in range of the signal?

 

With a range like that, I think you're outside the class of RFID units and into radio transponders. That would be like the ones on the Mass Pike that read a car's ID as it passes through a gate, though in New Hampshire they can do open-road toll collection, where the cars don't need to slow down. The transponder does have a battery and the receiver is drawing power all the time, but the current is small enough that the battery lasts for a couple of years.