Probably just an E911 address (enhanced emergency location system). Depending on locale, US addresses are usually standardized by ranges of units between mile markers or pegged to some sort of grid suited to the county or municipality. Often the address number itself will not only nail down the location in that way but may tell emergency dispatchers how far the location is from the nearest fire house, as a way of getting some kind of sanity check on the reported address.
It's reassuring for people who have heard about or experienced disastrous mixups in emergency assistance dispatched to wrong locations (wrong county, wrong state, wrong roadway suffix -- Place v. Avenue v. Road etc).
And of course, sigh.... it jacks up the paranoia among some people whose first thought is that they liked it a lot better when they lived in "the green house out by Sherman's Corners after you pass Weldon's place" rather than something that's practically a GPS marker for the black helicopters.