Background Rapid response to accident events can reduce fatal road events. It is unknown how stages of response, from occurrence to hospital arrival, impact the accident fatality rates.

Aim/Purpose To assess the relationship between fatal road accidents per county and accident response time.

Methods/Approach Data were pooled across eight years (2010 - 2017) from the Fatality Analysis Reporting System dataset. A total of 3,193 counties and county-equivalents were included in the study. The outcome variable was the fatality rate per county, defined as the yearly fatal counts per yearly county population. The predictor variables were the average duration of accident-to-notification, accident-to-EMS, accident-to-hospital, notification-to-EMS, notification-to-hospital, and EMS-to-hospital arrival times. The covariates were rurality, county-level racial, gender, age, unemployment, gross domestic product, and hospital utilization proportions. Measures of association were determined with Mann-Whitney U and Kruskal-Wallis tests. A negative binomial time series regression model was used to estimate the relative risks with significance set at a 95% confidence interval.

Results The median fatality rate per county was 6.90 per 100,000. There was a statistically significant difference in the median accident response times across the eight years (p<0.05). The average accident response times were significantly higher in rural counties compared to non-rural counties. In the unadjusted model, fatality rate increases by 1.9% (RR: 1.019; 95% CI: 1.016–1.022) and 3.0% (RR: 1.03; 95% CI: 1.028 – 1.032) for every minute increase in accident-to-notification and notification-to-EMS arrival times, respectively. In the adjusted model, a minute increase in accident-to-EMS and notification-to-EMS arrival times increases the fatal risk by 1.6% (RR: 1.016; 95%CI: 1.014–1.017) and 2.9% (RR: 1.027–1.031) respectively.

Conclusion Response time varies widely between rural and non-rural counties. Accident response events from accident occurrence to EMS arrival impact the greatest on fatality rate.

Significance/Contribution There is a need for more rapid response, especially in rural counties.