Road Safety for Canadian Practitioners: Module 2 – Measuring Safety

This module explains why quality data is fundamental to the development of effective road safety programs, projects and policies. It also illustrates the use of methods and tools needed for data-driven, evidence-based road safety applications. Different types and sources of safety data will be presented and used to illustrate applications in road safety management and project development.

This module has no prerequisite learning, although it is highly recommended that learners either complete Module 1 – Foundations of Road Safety, or bring an equivalent level of personal experience, before taking Module 2 – Measuring Safety.

There are six submodules, each of which includes a recorded lecture, a short quiz, and a handout with the lecture slides (PDF format). In addition, the course handout summarizes each submodule’s learning objectives, additional reading, and suggested exercises.

This course will run on desktop or laptop computers (Windows 7 or later, Mac OS X 10.9 or later) and on tablets or mobile phones (Android OS 5 or later, iOS 11 or later).

Learners will have access to the course for twelve months from the date of payment.

Learning objectives

After completing the following submodules, learners will be able to:

Submodule 2.1 – Introduction (24 minutes)

• Describe the differences among substantive, nominal, and subjective/perceived safety
• Define how substantive safety is measured

Submodule 2.2 – Safety Data (1 hour 55 minutes)

2.2.1 – Safety Data Types

• Identify the relevant components of safety critical data within collision records, traffic volumes, and road characteristics
• Recognize the impacts of missing, inaccurate, and non-timely data
• Discuss the components of supplemental data

2.2.2 – Safety Data Collection and Management

• Describe typical data collection methods and sources
• Identify the potential challenges of data collection and management
• Discuss the benefits of alternative data collection approaches

2.2.3 – Safety Data Quality

• Describe typical data gaps
• Describe how to assess data quality
• Relate the impact of data accuracy and reliability to road safety programs, projects, initiatives, and investments
• Explore the pitfalls of non-reliable safety measures

2.2.4 – Relationships among Safety Data

• Explain how key factors (e.g. speed, volume, time of day) could affect the frequency and severity of collisions
• Search source tools for safety research publications (e.g. TRID, TAC library)

Submodule 2.3 – Safety Performance Functions (SPFs) and Their Applications (65 minutes)

• Define different SPFs
• Identify where to obtain SPFs
• Demonstrate how to calibrate a borrowed SPF
• Give examples of SPFs
• Explain how an SPF can be used
• Describe how to develop an SPF using local data

Submodule 2.4 – Collision Modification Factors (CMFs) (46 minutes)

• Define collision modification factors and functions
• Identify the sources of CMFs
• Explain how to apply CMFs
• Illustrate the use of combinations of CMFs
• Describe how CMFs are developed
• Assess the factors to consider when selecting a CMF for a specific application

Submodule 2.5 – Empirical Bayes Method in Road Safety (20 minutes)                        

• Define the Empirical Bayes (EB) method
• Explain how the EB method can be used in road safety
• Offer examples and applications for the EB method
• List the strengths of using the EB method

Submodule 2.6 – Methods of Measuring Safety Performance (39 minutes)

• Define basic safety concepts including SPFs, the EB method, and regression to the mean
• Describe the strengths and weaknesses of the following safety performance measures, and their use:
  • Observed average collision frequency
  • Collision rate
  • Equivalent property damage only (EPDO) average collision frequency
  • Relative severity index
  • Critical rate
  • Predicted average collision frequency
  • Expected average collision frequency
  • Excess expected average collision frequency
  • EPDO expected average collision frequency
  • Probability of specific collision types exceeding threshold proportion
  • Excess proportion of specific collision types
  • Level of service of safety

Instructor

Geni Bahar, P.Eng., P.E., RSP2I – NAVIGATS Inc.

Geni is a civil engineer with 40 years of professional experience as a practitioner, researcher and trainer with a focus on road safety principles and applications enabling high-quality, evidence-based results. She was a member of the panel overseeing NCHRP Project 17-71 to develop the Highway Safety Manual, 2nd Edition, and has authored or co-authored many TAC publications including Guidelines for the Network Screening of Collision-Prone Locations, National Guidelines for Work Zone Safety in Canada, Pedestrian Crossing Control Guide, and Safety Performance of Bicycle Infrastructure in Canada. Geni has chaired TAC’s Road Safety Committee, served on the Board of Directors of the Transportation Professional Certification Board, and received the 2007 Transportation Person of the Year award from TAC and Transport Canada.

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