(b) The moneys in the fund shall be expended by the division of highways for constructing and maintaining industrial access roads within counties and municipalities to industrial sites on which manufacturing, distribution, processing or other economic development activities, including publicly owned airports, are already constructed or are under firm contract to be constructed. In the event there is no industrial site already constructed or for which the construction is under firm contract, a county or municipality may guarantee to the division of highways an acceptable surety or a device in an amount equal to the estimated cost of the access road or that portion provided by the division of highways, that an industrial site will be constructed and if no industrial site acceptable to the division of highways is constructed within the time limits of the surety or device, the surety or device shall be forfeited.