I am familiar with a rural location that I have been testing on your liveaddress API. It is 30 Ash Grove Lane Brooksville ME 04617. When I attempt a verification I get 0 matches, yet when I try a PO box for that same resident, I get a match to the location of the post office (where the PO Box is located).
So, what is the reason that the street segments are not in your database? Are they going to be included in the near future?
Our primary data source is the US Postal Service. And, While they don't know every address, they do have quite a few. With your questions the first place I go is to the USPS website (which always has the most up to date information – even more so than ours since we get updates monthly and they can update daily). Their address verification form is: zip4.usps.com - When you check that address on their site you get this. "The address you provided is not recognized by the US Postal Service as an address we serve. Mail sent to this address may be returned."
They don't show an Ash Grove Lane, but they do show an Ash Grove RD. (As a sidenote, GoogleMaps calls that road Steamboat Lane instead of Ash Grove Lane). As you can see from the screenshot, it's not a valid address. I cross-checked it with Fedex as well and they have a similar response. Fedex points out the on Ash Grove Rd, the number 30 is within the valid address range (which is 1-199). Further checking in our system shows that the only valid delivery point on Ash Grove is 106 Ash Grove Rd. It doesn't mean that #30 doesn't exist, just that The USPS doesn't deliver there. In the case of living in a city where street delivery is not available, most people resort to getting a PO Box. That is why the PO box that you listed is a valid address. For just that kind of situation, many people choose to enter both addresses, they physical one (for UPS and Fedex) and the mailing one (for USPS). In that case, the address could be listed as: address1: 30 Ash Grove Lane PO Box 100 (fake po box) city: Brooksville state: ME zip: 04617 or even this: address1: 100 (fake po box) address2: 30 Ash Grove Lane PO Box city: Brooksville state: ME zip: 04617 I worked in online retail sales for ten years and had many customers provide both addresses, just to make sure that the order gets delivered regardless of the delivery method (USPS/FEDEX/UPS). If you are using the API, you can send a request with an additional html header that will give you the results of the lookup and include invalid addresses (if they are within the valid range for the street).