The wake-effect--emergency vehicle-related collisions

Area of Science:

• Emergency Medical Services (EMS) Safety
• Traffic Safety Research
• Accident Analysis

Background:

• Emergency medical vehicle collisions (EMVCs) are a persistent issue for EMS systems.
• "Wake-effect" collisions, not directly involving the emergency medical vehicle (EMV), are anecdotally reported.
• Understanding wake-effect collisions could significantly alter EMV response protocols.

Purpose of the Study:

• To investigate the occurrence and frequency of wake-effect collisions compared to direct EMVCs.
• To test the hypothesis that paramedics report more wake-effect collisions than EMVCs.

Main Methods:

• A survey was administered to 75 paramedics from the Salt Lake City and Salt Lake County Fire Departments.
• The survey included open-ended questions about personal experience with EMVCs and wake-effect collisions.
• Statistical analysis determined the mean number of reported collisions and their 0.95 confidence intervals (CI).

Main Results:

• Seventy-three surveys were analyzed, reporting 60 EMVCs and 255 wake-effect collisions.
• The mean number of EMVCs per respondent was 0.82 (0.60-1.05 CI), while wake-effect collisions averaged 3.49 (2.42-4.55 CI).
• Specific mean values varied between the two fire departments but consistently showed higher wake-effect collision reports.

Conclusions:

• The study provides evidence that wake-effect collisions are a real phenomenon in emergency medical services.
• Wake-effect collisions appear to occur more frequently than direct emergency medical vehicle collisions.
• Limitations include recall and misclassification bias, necessitating further research into prevalence and impact.