RSA 234:18: Balance; Deficit.

Whenever, upon the completion of the bridge, the joint fund has not been expended in full, the unexpended balance shall revert to the state and municipality or municipalities in the same proportion as each contributed; and, whenever the cost of construction has exceeded the estimated cost, the municipality or municipalities interested shall forthwith, upon receipt of the itemized statement from the commissioner of transportation, remit to him their proportional shares of such additional cost.