Indiana Code Title 5. State and Local Administration § 5-16-2-1.5

Sec. 1.5. (a) Within sixty (60) days from the date on which bids are opened as specified in section 1 of this chapter, the political body or officer authorized to let contracts for public work or improvement shall award that contract and shall provide the successful bidder with written notice to proceed.  However, if general obligation bonds are to be sold to finance the construction which is the subject of the bid, ninety (90) days shall be allowed;  if revenue bonds are to be issued and approval by the utility regulatory commission obtained, or if special taxing district general obligation or revenue bonds are to be issued and sold to finance the construction, one hundred fifty (150) days shall be allowed.  A failure to award and execute the contract and to issue notice to proceed within the time required by this section entitles the successful bidder to either:

(b) If the successful bidder elects to reject the contract and withdraw his bid, notice of that election must be given to the political body or the officer authorized to let the contract in writing within fifteen (15) days of the sixty (60) day expiration date or any extension thereof.