Session No. 5A

Highway Safety Manual (HSM) Preview — Next Edition

Moderator: Eric Donnell, Director, Thomas D. Larson Transportation Institute, Penn State

Update on the 2nd Edition of the Highway Safety Manual (HSM2)

This presentation will provide details on the background of the Highway Safety Manual (HSM), the proposed outline for HSM2, significant changes to the content planned for HSM2, and the schedule for development of the second edition.

  • Darren Torbic, Texas A&M Transportation Institute

HOV/HOT Freeway Crash Prediction Method for the Highway Safety Manual

The first edition of the Highway Safety Manual includes a 2014 supplement predicting freeway safety performance; however, the HSM does not address freeway facilities with high-occupancy vehicle lanes or high-occupancy toll lanes (collectively referred to as HO lanes). There are many design elements of freeways with HO lanes that influence safety performance. The objective of this research included developing a predictive methodology that can be used to estimate crash frequency and severity for freeway facilities with HO lanes and to provide a spreadsheet implementation tool to assist agencies in implementing the predictive models. Data were collected in California and Washington to support development of a one-direction predictive method quantifying total crash and multiple-vehicle crash frequency. Severity distribution functions were developed to additionally quantify crash severity based on geometric and operational characteristics of freeway facilities with HO lanes. The method applies to freeway facilities with continuous HO lane access, buffer-separated HO lanes with intermittent access, and barrier/pylon-separate HO lanes with intermittent access between the HO lane(s) and the GP lanes. The method does not differentiate between HOV and HOT designation.

  • Scott Himes, PhD, P.E., Highway Safety Engineer, Vanasse Hangen Brustlin (VHB)  

Safe System via Social Practice: Design and Cultural Principles to Improve Road Safety

  • Seth LaJeunesse, Associate Director of Health and Community Sciences, University of North Carolina Highway Safety Research Center (HSRC)


Darren Torbic is a Research Scientist with the Texas A&M Transportation Institute. He has more than 27 years of research experience in the areas of highway safety, geometric design, traffic engineering, and pedestrian and bicycle transportation. He has served as principal investigator on numerous research projects for NCHRP, FHWA, and AASHTO. Torbic played a key role in several projects directly related to the development of the first edition of the HSM and is leading the development contract for HSM2 on NCHRP Project 17-71A.

Scott Himes is a Highway Safety Engineer with VHB in Raleigh, North Carolina. He is a 2006, 2007, and 2013 graduate of the Pennsylvania State University having most recently earned his PhD in Civil Engineering. His expertise focuses on development and application of data driven safety analysis methods, including development of network screening and project design-level safety performance functions, safety effectiveness evaluations, safety performance measure target setting models, and systemic safety approaches. He and his family reside in Apex, North Carolina, where they enjoy spending their free time exploring the various state parks and recreational areas when the extreme heat allows.

Seth LaJeunesse is the Associate Director of Health and Community Sciences at the University of North Carolina Highway Safety Research Center (HSRC). Having worked at HSRC for the past 11 years, LaJeunesse has designed studies that draw from psychology, sociology, and systems science to improve road safety practice.  He serves as the principal or lead investigator for several state and federally funded research endeavors, including safety projects and programs funded by the NC Department of Transportation, NC Governor’s Highway Safety Program, the National Cooperative Highway Research Program, the Federal Highway Administration, the Collaborative Sciences Center for Road Safety—a National University Transportation Center funded by the U.S. Department of Transportation—and the U.S. Department of Agriculture. Across all research projects, he aims to advance safe, equitable access to physical activity and community life.



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Dec. 9, 2021

2:00 — 3:15 p.m.



The Transportation Engineering and Safety Conference (TESC) attracts professionals from throughout Pennsylvania, the mid-Atlantic region, and the country. It is an authoritative source of information on pressing issues from some of the foremost experts in transportation today.

Thomas D. Larson Pennsylvania Transportation Institute

201 Transportation Research Building

The Pennsylvania State University

University Park, PA 16802-4710

Phone: 814-865-1891