If a website can tell what zip code you're in based on IP, that's good enough. If someone is using a VPN and their approximate location is obfuscated, the USER can choose to volunteer their location if they want localized ads.
Targeted advertising of any kind should be voluntary.
I also believe billboards should be taken down. Advertisers have been given carte blanche to hijack our eyes, ears, and attention without permission for far too long.