The following formula is to be used in the selection process for ranking discretionary bridge candidates.

The terms in the rating factor are defined as follows:

SR is Sufficiency Rating computed as illustrated in appendix A of the Recording and Coding Guide for the Structure Inventory and Appraisal of the Nation's Bridges, USDOT/FHWA (latest edition); (If SR is less than 1.0, use SR = 1.0);

ADT is Average Daily Traffic in thousands taking the most current value from the national bridge inventory data;

ADTT is Average Daily Truck Traffic in thousands (Pick up trucks and light delivery trucks not included). For load posted bridges, the ADTT furnished should be that which would use the bridge if traffic were not restricted. The ADTT should be the annual average volume, not peak or seasonal;

N is National Highway System Status. N = 1 if not on the National Highway System. N = 1.5 if bridge carries a National Highway System road;

The last term of the rating factor expression includes the State's unobligated balance of funds received under 23 U.S.C. 144 as of June 30 preceding the date of calculation, and the total funds received under 23 U.S.C. 144 for the last four fiscal years ending with the most recent fiscal year of the FHWA's annual call for discretionary bridge candidate submittals; (if unobligated HBRRP balance is less than $10 million, use zero balance);

TPC is Total Project Cost in millions of dollars;

HBRRP is Highway Bridge Replacement and Rehabilitation Program;

ADT′ is ADT plus ADTT.

In order to balance the relative importance of candidate bridges with very low (less than one) sufficiency ratings and very low ADT's against candidate bridges with high ADT's, the minimum sufficiency rating used will be 1.0. If the computed sufficiency rating for a candidate bridge is less than 1.0, use 1.0 in the rating factor formula.

If the unobligated balance of HBRRP funds for the State is less than $10 million, the HBRRP modifier is 1.0. This will limit the effect of the modifier on those States with small apportionments or those who may be accumulating funds to finance a major bridge.