For the purpose of determining eligibility to sign a nominating petition or a petition proposing a public question the terms “voter”, “registered voter”, “qualified voter”, “legal voter”, “elector”, “qualified elector”, “primary elector” and “qualified primary elector” as used in this Code or in another Statute shall mean a person who is registered to vote at the address shown opposite his signature on the petition or was registered to vote at such address when he signed the petition. Any person, otherwise qualified under this Section, who has not moved to another residence but whose address has changed as a result of implementation of a 9-1-1 emergency telephone system shall be considered a “voter”, “registered voter”, “qualified voter”, “legal voter”, “elector”, “qualified elector”, “primary elector”, and “qualified primary elector”.