Applying the Safe System Approach to Transportation Planning, Design, and Operations (2025)
Chapter: Safe System Practice Extraction
Safe System Practice Extraction
Considering the reviewed Safe System principles and implementation frameworks, this section describes how our team carried out a sweeping review of the academic and trade (gray) literature on the Safe System approach as well as other guiding frameworks from peer countries that have significantly improved road user safety over the past three decades:
- Safe System approach
- Road to Zero
- Vision Zero
- Target Zero
- Toward Zero Deaths
- Sustainable Safety
- Traffic safety culture
- One Network, Movement, and Place framework
- Safety-related asset management strategies
Search Strategy
In addition to researching guiding safety frameworks, the team developed the following list of keyword search terms organized around diverse safety countermeasures, vehicle technologies, safety analysis methods, safety procedures, and specific road user groups. We then systematically searched for traffic safety-relevant literature in Transport Research International Documentation (TRID), PubMed, Web of Science, and Google Scholar:
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rural road safety systemic safety self-explaining road* safe road users safe roads emergency response safety polic* drivers AND older OR young safety campaign* traffic impact analysis level of service OR quality of service traffic volume* travel demand management older road users advanced driver assistance systems (ADAS) design speed* maintenance |
traffic safety culture OR safety culture asset manag* youth OR young people OR child* safe vehicles post-crash care Intelligent Transportation Systems (ITS) tribal communit* emergency management* risk management long-range plan* capacity conflict* time to collision forward collision warning OR forward collision avoid* location efficienc* operating speed* operations |
risk assessment* health impact assessment* injury surveillance safe speeds project priorit* cycl* OR bicycl* transit riders OR transit users low vision or blind* automatic emergency braking impact speed* congestion pric* target speed* post-encroachment time blind spot warning backcasting multi-criteria analysis |
Next, the team saved 549 papers in SciWheel, a citation management software available through University of North Carolina (UNC) libraries. From these 549 papers, the team identified 465 that likely described safety practices and management systems.
Following identification of potentially relevant papers, team members (1) summarized study purposes, methods, and findings and (2) extracted safety practices—concrete, visualizable safety-oriented acts that can be routinely carried out or applied over a broad geographic area. To ensure reliability across members carrying out the extractions, the project manager led the team through a virtual tutorial on how to summarize and extract key information from papers, practicing a few applied examples together. Team members also summarized those papers that did not feature a visualizable safety practice to capture more holistic approaches or theoretical work. In addition to summarizing each paper, the team provided a brief description of how the practice is related to safety and protecting road users (e.g., “reducing vehicle speeds will improve reaction time for drivers in the event of a potential conflict and reduce the risk of death or serious injury should a crash occur”). Alternatively, members were tasked with indicating whether a practice would conceivably deepen our understanding of injury contributors (e.g., systemic or risk-based safety assessments).
These procedures yielded a total of 75 safety practices, procedures, and countermeasures, all of which are displayed in Tables 12 through 17. The team organized these safety practices into six interrelated domains:
- Policy
- Planning
- Design
- Operations and Maintenance
- Law Enforcement
- Post-Crash Response
To acquire a better understanding of professionals’ perceptions of these 75 safety practices, the team designed a practitioner survey, the development process and results of which are described next.
