5.3.1 Overview

The HSM was developed by AASHTO. The first edition of the HSM was published in 2010 and is the premier guidance document for incorporating quantitative safety analysis in the project planning and development processes. With an emphasis on using analytical methods to quantify safety, the HSM helps practitioners understand the safety effects of decisions in planning, design, operations, and maintenance efforts. This science-based approach is intended to take the guesswork out of safety analysis. A supplement to the HSM was published in 2014 to provide additional guidance on performing analysis on freeways. The HSM is for practitioners at the State, county, MPO, local agency, tribal, and consultant level.
This section is intended to be an introduction into the HSM, not a comprehensive overview. Reference the HSM or the HSM website for additional detailed information.
The most recent HSM, 1st Edition, 2010, consists of three volumes and a supplement. It is divided into four parts, which are further described in the following sections:
  • Part A – Introduction, Human Factors, and Fundamentals (Volume 1);
    • Chapter 1 – Introduction and Overview
    • Chapter 2 – Human Factors
    • Chapter 3 – Fundamentals
  • Part B – Roadway Safety Management Process (Volume 1);
    • Chapter 4 – Network Screening
    • Chapter 5 – Diagnosis
    • Chapter 6 – Select Countermeasures
    • Chapter 7 – Economic Appraisal
    • Chapter 8 – Prioritization
    • Chapter 9 – Safety Effectiveness Evaluation
  • Part C – Predictive Method (Volume 2 and Supplement); and
    • Chapter 10 – Predictive Method for Rural Two-Lane, Two-Way Roads (Volume 2)
    • Chapter 11 – Predictive Method for Rural Multilane Highways (Volume 2)
    • Chapter 12 – Predictive Method for Urban and Suburban Arterials (Volume 2)
    • Chapter 18 – Predictive Method for Freeways (2014 Supplement)
    • Chapter 19 – Predictive Method for Ramps (2014 Supplement)
  • Part D – CMF (Volume 3)
    • Chapter 13 – Roadway Segments
    • Chapter 14 – Intersections
    • Chapter 15 – Interchanges
    • Chapter 16 – Special Facilities and Geometric Situations
    • Chapter 17 – Road Networks
shows these HSM parts and chapters in flowchart format.
HSM Parts
Figure 5-1: HSM Parts
The information contained within the HSM is not a legal standard of care and is intended to aid agencies in their efforts to integrate safety into their decision-making processes. The HSM was not created to replace or substitute the exercise of sound engineering judgement. The HSM does not supersede publications such as the TMUTCD, the AASHTO
A Policy on Geometric Design of Highways and Streets
 (Green Book), or other AASHTO and agency guidelines, manuals, and policies.