A new report says that Gov. Chris Christie knew that the ARC Tunnel project overruns could be as low as $1 billion. The Star-Ledger was told by sources close to the presentation made by Transportation Secretary Ray LaHood, that the cost overrun could hit $1 billion on the low end. Christie said the overrun was between $2.3 billion and $5.3 billion. A final decision is expected on Friday by Christie on the work.