FHWA also conducted a national evaluation of the HSIP to estimate expected program results using the project information from the 2016 HSIP reports. The purpose of the evaluation was to estimate a national benefit cost ratio for the HSIP. The HSIP national benefit cost ratio provides an indication of the programs national impact and the benefits the public can expect from investments in the HSIP.

The evaluation methodology makes use of the full project listing information from 50 States plus the District of Columbia (2016 HSIP Database) and associated crash modification factors (CMFs) from the CMF Clearinghouse, the Fatality Analysis Reporting System (FARS), the Highway Performance Monitoring System (HPMS), the Highway Safety Information System (HSIS), FHWA, and various reports. The following steps indicate how to apply the selected methodology for projects in the 2016 HSIP Database with complete data:

1. Calculate the estimated crash reduction for each project group
   1. Estimate a "before" crash rate using data from FARS, HPMS, and HSIS.
   2. Identify appropriate CMFs from the CMF Clearinghouse.
2. Calculate the monetary benefit for each project category by converting crash savings to dollar amounts.
   1. Update crash severity costs (K, KA, KABC, ABC, KABCO) to 2015 dollars using information from Council et al^[5] and an internal FHWA memo^[6].
3. Divide annual monetary benefit by the annualized project cost to calculate the benefit-cost ratio.
   1. Assume a service life per treatment type using information from the Service Life and Crash Cost User Guide available on the CMF Clearinghouse.
4. Calculate a program wide benefit-cost ratio by averaging the ratios from all project groups.
   1. Weight the average based on HSIP funds spent for a project to account for project groups which were more prevalent in the data.

For this reporting cycle, it was possible to calculate the expected project level benefit cost ratios for 1,077 segment and intersection based projects, which is approximately 24 percent of the projects listed in the 2016 HSIP Database. Table 4 presents the weighted results (based on amount of HSIP funds that were spent for that project). Many projects had a range of years for the assumed service life, so the table presents the BC ratio according to the minimum and maximum service lives.

The values in Table 4 (4.355 to 6.511) represent the range of BC ratios for the HSIP program for segment and intersection based improvement projects, depending on the minimum or maximum service life of the treatment and discount rate. Comparatively, the range for the 2015 HSIP project listing was 4.523 to 7.123.

Table 4. Weighted BC Ratio for Segment and Intersection Based Projects (weight based on total project cost)

Many projects could not be included in analysis because they were either missing key data elements (e.g., number of miles or intersections treated, CMF, project cost, etc.) or were non-infrastructure projects. The calculated benefit-cost ratio for each of the 1,077 projects relied heavily on assumptions for each project regarding the applicable CMF, service life, crash rate, and injury severity cost.