Applying the Safe System Approach to Transportation Planning, Design, and Operations (2025)
Chapter: Background: Defining the Safe System
Background: Defining the Safe System
For the past decade, there has been a promising rise in commitment to advancing the safety of our transportation system to realize a future without serious and fatal injury on our roads (Shi et al., 2023; Evenson et al., 2023). Even more recently, organizations and agencies have adapted road safety philosophies from abroad to propose a Safe System approach (U.S. Department of Transportation Federal Highway Administration, 2019). A consensus has been forming around ways to define and frame this approach. Most typically, a Safe System is thought to be shaped by both pragmatic (e.g., redundancy is crucial, safety is proactive) and ethical principles (e.g., death and serious injury is unacceptable) and comprised of safety pillars or elements (i.e., safe road users, safe vehicles, safe speeds, safe roads, post-crash care) (Vision Zero Network, 2023; FHWA, 2019).
The Safe System paradigm represents a pivot away from the “Responsibility” paradigm, which emerged in the 1980s in the United States (Norton, 2015). Whereas until recently, speed was considered safe—assuming drivers were responsible—and other road users were generally thought to be responsible for their own safety and the safety of others, the Safe System paradigm recognizes the fallibility of humans and places greater responsibility on system operators for keeping road users safe and protected.
The Safe System pillars, like the Es of Traffic Engineering, Enforcement, Education, and Emergency Services, emphasize the importance of multisectoral coordination (Norton, 2015). Yet though such coordination may approach safety as a “systems fashion,” it is not yet a “safe system approach” (Job et al., 2022). The problem is not the definition of the Safe System elements; instead, it is the fact that actions can readily be framed as adhering to the Safe System elements, but not be in alignment with fostering a system that eliminates road trauma. For example, improved signage can be placed under the Safe Road Users, Safe Roads, and Safe Speeds elements, but not represent a Safe System approach. Improved signage does little to protect road users in the event of inevitable mistakes. A Safe System is guided by a set of principles that direct what has to be performed under each element, not simply the use of the elements themselves (Green et al., 2024).
A principle-driven Safe System program is consistent with Job’s and colleagues’ (2022) conceptualization of the “Ultimate Safe System,” which they define as follows:
“In road transport, the Ultimate Safe System is one in which road users cannot be killed or seriously injured regardless of their behavior or the behavior of other road users.”
Additionally, this Ultimate Safe System definition aligns with the Netherland’s “Sustainable Safety Vision,” which is organized around three facts about humans:
- People are vulnerable.
- People can be reckless and make mistakes.
- People do not always follow rules. (Shi et al., 2023)
This Interim Report is organized as follows. First, we present an endorsed definition of a Safe System, framed predominantly by its guiding principles, which give shape to the resulting pillars or elements of a Safe System. Then, we introduce a Safe System Implementation Framework, focusing on organization principles that peer countries have adopted. This is followed by a description of our Safe System practice extraction methodology, which was informed by Safe System principles and a broadly employed implementation framework. We then describe our approach to designing a practitioner survey, the results of which include professionals’ rating of
practices’ feasibility and safety impacts, as well as our focus group protocol and thematic results. The report ends with a distillation of what the team has learned and how we leveraged this knowledge to develop ideally useful and transformative guidance.
