A best-and-final round of bidding on the Tappan Zee Bridge replacement project is scheduled to take place in a few weeks and a conditional award of a design-build contract to an apparent low bidder is expected before election day, Nov. 6, sources say.

Negotiations on a final contract could extend into next year, and a notice to proceed will come when Gov. Andrew Cuomo makes a firm commitment of funds. This is expected to include a $2.9-billion TIFIA loan to be delivered by US DOT Secretary Ray LaHood before he retires.

The design-build bid prices are expected to be well below the state’s widely publicized $5.2-billion estimate. That estimate is for the full project cost, including about 10% for non-contractor expenses. So a low bid for the design-build contract of close to $4 billion is possible, sources say.