HSS™

Highway Safety Software™

New Version

HSS 2025

HSS 2025 includes the addition user-defined crash modification factors (CMFs) and map-based segmentation for rural and urban facilities.

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Highway Safety Software

The Highway Safety Software (HSS) performs Crash Prediction evaluations in roadway facilities based on the Highway Safety Manual (HSM). As presented in the HSM (©️ 2010 by the American Association of State Highway and Transportation Officials — AASHTO), the base model to predict crash frequency was built to consider the local infrastructure and operational characteristics. Safety Performance Functions (SPF) and the Crash Modification Factors (CMFs) are presented for the various facility types. An additional Calibration factor, Cr, can adjust the model for a condition other than the one for which it was developed.

The Highway Safety Software (HSS) faithfully implements the Predictive Method of AASHTO’s 1^st Edition HSM and its supplement HSM 2014, allowing for local and state-level calibration for parameters. This release of the HSS includes updated modules to implement the Highway Safety Manual Predictive Models.

What can HSS model?

All facility types covered by the HSM can be modeled in HSS, which include the following:

• Rural two-lane highways
• Rural multi-lane highways
• Urban / suburban arterials
• Freeway segments
• Freeway ramps / interchanges

• Intersections
- Traditional Signalized Intersections
- (three^[1] and four approach signalized)
- Stop-Controlled Intersections
- (three and four approach stop)
^[1] Only for urban/suburban arterials
• Roundabouts (NCHRP Project 17-70)

HSS can conduct a standalone evaluation of a segment/intersection or analyze corridors composed of a series of segments and intersections.

HSS Features

HSS can help with the following:

Can analyze all facility types covered in the Highway Safety Manual – HSM chapters 10-12, 18-19, plus NCHRP 17-70
Conduct an individual evaluation of an intersection or segment by facility type
Allow input of multiple segments and intersections in facility analysis
Add/exclude individual intersections/segments
Allow the application of the Empirical-Bayes method when historical crashes are available
Allow input calibration factors described in the Appendix to HSM Part C
Provides multiple-segments/intersections text reports
Provides export to CSV file functionality
Includes Benefit-Cost analysis

HSS is part of the HCS package.

Support

We provide support to our customers in an expedited way. Our customers only need to let us know their questions or where they stopped in their analyses, and the McTrans HSM Subject Matter Expert (SME) team will get back to them near-instantly to provide help and support.