As described by the FHWA, HSIP is a core federal aid program that aims to significantly reduce traffic fatalities and injuries on all public roads, including on-system roads, off-system roads, and roads on tribal land. The HSIP involves a data-driven, strategic approach to improving highway safety on all public roads with a focus on safety performance. HSIPfunded projects either address historical crashes or focus on high-exposure roadway features (systemic safety). HSIP-funded projects are also evaluated for costeffectiveness. The benefit-cost (B/C) analysis uses the Safety Improvement Index (SII) formula. The SII is the ratio of the annual savings in preventable crash costs to the cost of constructing the proposed improvement. A sample SII calculator is provided in

Appendix F, Section 1 – SII Calculators

. A link to TxDOT’s Highway Safety Engineering Website (including the SII calculator spreadsheet) can be found in

Appendix F, Section 3 – External References (Reference 6).