ORS § 366.516
The Department of Transportation may incur obligations to be paid from the State Highway Fund for the construction, reconstruction, improvement, repair or maintenance of highways, streets and bridges in excess of the amount then standing to the credit of the State Highway Fund if in the opinion of the department there will be sufficient funds available for the payment of such obligations when they become due and payable and all other debts, obligations and expenses chargeable against the State Highway Fund including those amounts that are required by law to be set aside from the State Highway Fund for particular purposes. Obligations incurred under the authority of this section need not be payable in the same biennial period during which the obligation is incurred.
ORS 366.516