does DBI require unix-odbc drivers to be installed to work?

No, DBI only requires DBD's -- data base drivers

I assumed the drivers come along with the DBI/DBD:ODBC etc..?

This usually isn't the case; DBD::SQLite is an exception

I installed both DBI and DBD::ODBC but it says cant locate odbc.

What is the exact error message (copy/paste)?