Admin Boundaries, Postal Codes and CDPs

The TIGER import brings in US Census Designated Places as a Level 8 Administrative boundary. As far as I understand CDPs are statistical boundaries and should be deleted. Is that true?

The town I’m working is defined by a level 8 boundary as it should be but the town is huge, 770,000 people.
Unincorporated areas within the town have anywhere from 40,000 to 80,000 people. If not in one of the towns incorporated villages most people refer to their postal code as their “village” Should I use the postal code a 9th level administrative boundary?

Correct - in most areas, CDPs are not meaningful, but they do have meaning in some specific parts of the country. It would be best to confirm this with others in the region, or check with the talk-US mailing list.

I’m not clear myself weather to use the postal code or city administrative code as the addr:city element. The TIGER postal codes (ZCTA - Zip Code Tabulation Areas) are just an approximation, and do not match current USPS zip code assignments. And USPS zip code assignments are proprietary. So generally, postal codes should not be entered into OSM as an area.