Once published, the provisional lists will have to be agreed upon by all political parties before ballots are printed.

VOA: standard.2009.09.29

Provisional ballots are counted after regular ballots and are subject to challenges from the parties or voting officials.

WSJ: Big Turnout Stresses Election System

Election Protection reported that election workers were incorrectly offering provisional ballots to voters because of equipment breakdowns in Philadelphia.

WSJ: Big Turnout Stresses Election System

They also note that voters who don't have ID can cast provisional ballots.

NPR: Study Links Voter ID Rules to Non-Voting