A Guide to Applying the Safe System Approach to Transportation Planning, Design, and Operations (2025)
Chapter: 7 Safe System Post-Crash Response
CHAPTER 7
Safe System Post-Crash Response
In a Safe System, post-crash response is the end and the beginning of the line. It is the last layer of protection and the first statement on the safety performance of the system. Safe System-consistent post-crash response bolsters reliable crash notification and data collection systems, efficient and effective emergency services and medical treatment, and a capacity to continually improve the quality of services (WHO 2017). In this way, post-crash response within a Safe System advances collaboration among medical professionals, law enforcement, emergency medical service (EMS) professionals—inclusive of emergency medical technicians (EMTs), advanced EMTs, and paramedics—and transportation professionals (Khan and Das 2024).
At present, EMS professionals in the United States are generally underresourced in the form of low salaries for paramedical clinicians and a lack of continuing education and training opportunities for these professionals. Post-crash response is also largely disconnected from partners in healthcare and often dangerous to emergency responding personnel, given their exposure to road and air ambulance crashes on the way to and from crash scenes and at crash scenes (Maguire 2011; Maguire et al. 2022). Further, cellphone coverage is often limited, which can lead to an increase in emergency response times (Gonzalez, Ems, and Suri 2016). Moreover, vehicles’ event data recorders tend to be triggered by deployed airbags, which require striking a solid fixed barrier at 15 mph to deploy and, therefore, could potentially lead to an under-recording of crashes involving vulnerable road users (European Commission: Directorate-General for Mobility and Transport, McCarthy, and Hynd 2014; International Transport Forum 2019).
A paradigm shift in post-crash response is necessary and possible. This shift will require greater investment in reliable crash notification and communications, a major strengthening of various pre-hospital care functions, and improvements to safety investments (including post-crash rehabilitative care and crash data collection and storage) made possible through linked road safety and trauma data and research.
7.1 Key Post-Crash Response Strategies
To apply the principles of a Safe System in the context of post-crash response, the following strategies can contribute to a Safe System:
- Invest in crash notification and communications systems.
- Strengthen pre-hospital care functions.
- Enhance safety investments via research and sharing of trauma and road safety data.
Invest in Crash Notification and Communications
Robust and reliable post-crash responses rely on the effective functioning of integrated systems to detect serious crashes on the network and communicate important details about crash incidents to emergency responders. As crash events are often difficult to predict, the adoption, diffusion, and integration of advanced automatic crash notification (AACN) systems is central to notifying emergency services of where potentially life-threatening crashes occur on the roadway network. As observed by Valente (2024), AACN systems can greatly reduce the time elapsed between a crash event and the activation of the 911 system. This is especially true for more remote roadway departure crashes and ones in which crash victims have become incapacitated (Institute of Transportation Engineers 2019). Other scholars agree that automated communication of crash location is critical to reducing the severity of injuries that take place after EMS arrives at the crash scene (Ritter, Williams, and Wijetunge 2022) and that post-crash care should be incorporated into safety planning to improve crash scene management and prevent secondary crashes and injuries (Liu 2022). AACN systems of the near future will be able to share information on the probable injury severity of crash-involved parties by way of telemetry-measured operating speeds of crash-involved vehicles (Institute of Transportation Engineers 2019).
Strengthen Pre-Hospital Care Functions
To foster a Safe System, post-crash response would benefit from buttressing pre-hospital care functions. Pre-hospital interventions aim to reduce the severity of injury consequences once a traffic crash has occurred. This involves supporting roadside and in-emergency-vehicle care provision and transport to hospitals and trauma centers. As Mohan and colleagues (2020) argue, post-crash, pre-hospital care requires strengthening of the following emergency service elements:
- Extrication capabilities—the ability to safely and swiftly remove occupants who have been trapped in crash-involved vehicles
- Vehicle capabilities—the ability for ambulance and emergency vehicles to safely convey injured parties to hospitals and trauma centers in emergency cases
- EMS professionals’ and first responders’ capabilities—medical training for stabilizing acute trauma cases on scene, for example, being able to recognize opioid overdoses and appropriately administer opioid antagonists (e.g., naloxone) and to stop patients’ bleeding
- Broader distribution of trauma-equipped hospitals across the region to reduce the time of transport
- The capacity to safely and efficiently transport patients to trauma-equipped hospitals from incident sites [e.g., investing in emergency vehicle priority schemes (Frith et al. 2018)]
Enhance Safety Investments Via Research and Sharing of Trauma and Road Safety Data
Integrating trauma with road safety data can significantly improve decision-making on emergency medical care for road crash victims (Hakkert, Gitelman, and Vis 2007; Hosseinzadeh et al. 2022). A trauma registry would allow analysts to monitor the performance of post-crash response and associated qualities of emergency care (Fosdick et al. 2024). Further, rigorous data collection and data sharing across agencies (e.g., police departments, transportation departments, and hospitals) can lead to a better understanding of road safety issues and enhance the context-appropriateness of safety investments (Finkel et al. 2020; International Transport Forum 2016).
Severe injury prevention, subsequently, would be facilitated by equitable access to holistic rehabilitation services, which could mitigate the risk of long-lasting physical and psychological damage among people involved in serious crashes (Fosdick et al. 2024). It is worth noting that, via
the Decade of Action for Road Safety, the World Health Organization (WHO) has been advocating for decades for the provision of early rehabilitation for crash victims and integrated support for bereaved family and friends of victims (WHO 2011; WHO 2021).
Linked road safety and trauma data could eventually contribute to a rise in emergency service professionals’ crash predictive capabilities and in vehicle safety design features (Liu 2022). For example, by regularly coordinating with planners and engineers to discern those locations on the transportation network that harbor serious crash potential and those times of year and day during which injurious crashes are more likely to occur, EMS and transportation professionals could enhance their abilities to anticipate serious crashes. In fact, research indicates locations and times severe crashes are more likely to manifest:
- Lane departure fatalities are most likely to occur along rural roads with high horizontal curve density, or the number of horizontal curves per mile of roadway (Lord et al. 2011), especially at curves with radii ≤ 500 ft and at hillcrest locations under cloudy weather conditions (Hossain et al. 2023).
- Motorcyclist fatalities are more likely to occur at curves on rural two-lane undivided highways (Xin et al. 2019). Further, left turns at intersections coupled with wet pavement conditions can lead to serious injuries for motorcyclists (Das, Mousavi, and Shirinzad 2022).
- Pedestrian fatalities tend to occur on higher-speed (≥ 30 mph) urban principal arterials surrounded by land uses designed to predominantly accommodate automobile use (e.g., regional highway corridors) (Schneider et al. 2021). Further, most pedestrian fatalities occur under dark conditions (Sanders, Schneider, and Proulx 2022).
- Severe injury among bicyclists is more likely to occur at nonorthogonal (or skewed) intersections, along straight street segments, and at nighttime and involve large trucks or buses (Asgarzadeh et al. 2017).
- All fatal and serious crashes begin rising in July and peak in October each year. These crashes are also more likely to occur between the hours of 3:00 p.m. and midnight (National Center for Statistics and Analysis 2023).
7.2 Study-Identified Post-Crash Response Practices
Branching off from post-crash response strategies are more specific safety practices. The example practices outlined in Table 12 align with the strategies of Safe System post-crash response in that they are designed to strengthen crash notification systems and pre-hospital care functions and enhance safety interventions via research and the cross-sectoral sharing of trauma and road safety data.
The research team identified 11 Safe System–aligned post-crash response practices from the literature review phase of the research and presented them to safety practitioners via an online survey (see Appendix F). Survey participants were asked to rate the safety impact and the financial, social, and political feasibility of each practice based on their professional experience and institutional knowledge. Participant responses on the perceived impact and feasibility of the 11 post-crash response practices can be found in Appendix F.
In keeping with Safe System principles and policy strategies, the team determined whether each post-crash response practice would reduce road users’ exposure to severe crash types (e.g., run-off-road, head-on, intersection, pedestrian, bicyclist, or motorcyclist crashes) and the likelihood road users would be involved in one or more of these crash types:
- Exposure reflects the number of people with the potential to be involved in serious crash types.
- Likelihood reflects the probability road users will be involved in a crash.
- Severity reflects the chances a crash will result in a fatality or serious injury to the road users involved.
Table 12. Safe System post-crash response practices.
| Example Practice | How Safety Is Improved | Exposure | Likelihood | Severity | Improves IRA, PCC, or CD1 | Costs2 |
|---|---|---|---|---|---|---|
| Forming a task force or community coalition of law enforcement, transportation, public health, members of the community, and other partners to investigate serious crashes and report findings and proposed changes to the public | Incorporates multiple perspectives on crash contributing factors and introduces system administrator accountability to prevent further incidents | − | − | − |  |
Low |
| Training law enforcement and transportation staff to coordinate post-crash reporting at crash sites | Places crashes into a broader transportation context, thereby minimizing focus on the errors of individual road users | − | − | − | |
Low |
| Developing joint action plans with emergency services partners to integrate operational planning with emergency services planning | Aligns roadway operations with emergency services thereby streamlining emergency response | − | − | − | |
Medium |
| Linking police with EMS/hospital data for persons injured in motor vehicle crashes | Provides injury surveillance teams with more accurate and complete data on the state of road trauma in a region | − | − | − | |
Medium |
| Upgrading analog 911 infrastructure to Next Generation 911 (commonly referred to as NG911) to create a faster, more resilient system that facilitates public reporting to the 911 network | Hastens and shores up the public’s ability to report geolocated crashes on the network | − | − | |
|
High |
| Placing serious crashes in a time- or place-based context when engaging news media partners | Encourages the public to perceive the transportation system as needing addressing rather than the people involved in crashes | − | − | − | |
Low |
| Example Practice | How Safety Is Improved | Exposure | Likelihood | Severity | Improves IRA, PCC, or CD1 | Costs2 |
|---|---|---|---|---|---|---|
| Establishing a traffic incident management system that documents roadway and incident clearance times, as well as secondary crashes | Provides a means of documenting the performance of emergency service operations and can be used to improve the traffic incident management if the documentation were required, e.g., what did not work, how can the system be improved, etc. | − | − | − | |
Medium |
| Instituting automatic crash notification (ACN) for vehicle collisions with people walking, cycling, or rolling | Hastens the reporting of crashes involving road users who may be unable to self-report crash incidents (e.g., via crash notification on road users’ smartphones) | − | − | |
|
Medium |
| Installing ACN systems on more remote, rural roadways | Hastens the reporting of crashes that occur in more remote, rural locations (e.g., via embedding crash notification in guardrails or on road users’ smartphones) | − | − | |
|
High |
| Encouraging and facilitating public use of self-reporting (via mobile app or survey) to capture collisions and other events falling outside the scope of traditional crash reporting (e.g., near misses, pedestrian and bicyclist falls) | Adding self-reported crashes to traditional crash reporting can provide system administrators with a more holistic sense of single-user injuries and crash potential throughout the network | − | − | − | |
Low |
| Deploying unmanned aerial systems to conduct route monitoring, crash incident verification, secondary crash detection, and response vehicle routing to and from the crash site | Improves emergency service units’ ability to efficiently and safely access crash sites | − | − | − | |
Medium |
Note: − = Not applicable.
1 IRA = injury risk assessment, PCC = professional and community coordination, CD = crash diagnoses.
2 Costs correspond to the total financial cost associated with a policy or practice, including labor, equipment, and infrastructure (Low ≤ $100k; Medium = $100k−$1 million; and High ≥ $1 million in total or per year).
- Improves injury risk assessment, professional and community coordination, or crash diagnoses reflects a practice’s ability to estimate road-user injury risks associated with land use, policy, or engineering interventions; to improve coordination among professionals in different sectors and with the public; or to uncover contributing factors to serious crash events.
Table 12 provides example post-crash response practices and their change mechanisms (i.e., the steps or processes responsible for improving road users’ safety).
Implementing Safe System Post-Crash Response Practices
Safe System post-crash response strategies and practices strengthen crash notification systems and pre-hospital care functions and enhance safety investments via research and the sharing of trauma and road safety data.
To begin implementing Safe System–aligned post-crash response practices, consider the following steps and substeps:
- Identify at least one significant safety problem. Identification and prioritization of a safety problem might be based on the following:
- – Severity and magnitude of the safety problem
- – Disproportionate harm endured by some community members by the problem
- – Importance of addressing the problem to community representatives
- – Availability of resources to address the problem
- Once a safety problem has been identified and prioritized, ask the following two questions:
- –To what extent does a proposed practice to address the identified problem align with Safe System–aligned post-crash response strategies?
- Invest in crash notification and communications
- Strengthen pre-hospital care functions
- Enhance safety investments via research and the sharing of trauma and road safety data
- – To what extent does a proposed practice address the following?
- Users’ exposure to serious crashes
- The likelihood of serious crashes
- The severity of crashes when they occur
- Improvements to injury risk assessment, professional and community coordination, or crash diagnoses
- –To what extent does a proposed practice to address the identified problem align with Safe System–aligned post-crash response strategies?
For example, in step 1, if a safety team identifies and prioritizes responding more rapidly to severe intersection crashes, they might pursue developing joint action plans with emergency services partners to integrate operational planning with emergency services given the disproportionate harm endured by some community members by the problem and the availability of resources to address the problem.
Then, in step 2, a safety team might conclude that integrating operational planning and emergency services aligns with the Safe System strategy to strengthen pre-hospital care functions. They might also conclude that integrated operations and emergency service planning can improve professional coordination between operations and emergency services planners.
At this point, a team should reflect on whether a selected safety practice (1) aligns with one or more Safe System strategies; (2) can significantly reduce the likelihood and severity of users’ experience with crashes or enhance injury risk assessment, professional and community coordination, or crash diagnoses; and (3) is feasible given available resources to institute the practice. If the team concludes that all three criteria are satisfied, the practice should be considered for implementation, and the safety team could follow the steps outlined in Table 13. However, if one or more of these three criteria are not satisfied, teams are recommended to start over from step 1 until all three criteria are satisfied.
Table 13. Post-crash response practice implementation steps and example elements.
| Step | Example Step Elements |
|---|---|
| Determine the practice’s intended goals, the factors that contribute to practice performance and interactions among factors, what key factors might look like in the future, and success indicators. |
|
| Enable innovation of practices to meaningfully respond to foreseen and unforeseen opportunities. |
|
| Monitor indicators of performance in relation to practice objectives, key factor indicators and thresholds for adjusting the practice, and interested party feedback on the practice. |
|
| Improve learning of practice performance to make necessary adjustments to strengthen practice performance or to change up the practice altogether. |
|
For illustrative purposes, a safety team looks to develop joint action plans with emergency services partners to integrate operational planning with emergency services planning. Table 13 provides recommended steps to implement this safety practice along with elements to consider within each step.
Conclusion
A shift toward Safe System–aligned post-crash response practices is possible and necessary for the United States to realize zero deaths and serious injuries on the nation’s roadways. Post-crash response professionals and partners can be supported through advanced crash notification and communications about probable injuries. These professionals would also benefit from a strengthening of prehospital care functions, such as roadside and in-vehicle care provision. Moreover, post-crash response would be enhanced via research and the sharing of trauma registry data among EMS professionals, law enforcement, and transportation professionals to inform the development of serious crash preventive policies, as well as proactive planning and design practices.
