Can ambulance dispatch categories discriminate traffic incidents that do/do not require a lights and sirens response?

Purpose: Traffic incidents vary considerably in their severity, and the dispatch categories assigned during emergency ambulance calls aim to identify those incidents in greatest need of a lights and sirens (L&S) response. The purpose of this study was to determine whether dispatch categories could discriminate between those traffic incidents that do/do not require an L&S response. Design/methodology/approach: A retrospective cohort study of ambulance records was conducted. The predictor variable was the Traffic/Transportation dispatch categories assigned by call-takers. The outcome variable was whether each incident required an L&S response. Possible thresholds for identifying dispatch categories that require an L&S response were developed. Sensitivity and specificity were calculated for each threshold. Findings: There were 17,099 patients in 13,325 traffic incidents dispatched as Traffic/Transportation over the study period. “Possible death at scene” ‘had the highest odds (OR 22.07, 95% CI 1.06–461.46) and “no injuries” the lowest odds (OR 0.28 95% CI 0.14–0.58) of requiring an L&S response compared to the referent group. The area under the ROC curve was 0.65, 95% CI [0.64, 0.67]. It was found that Traffic/Transportation dispatch categories allocated during emergency ambulance calls had limited ability to discriminate those incidents that do/do not require an L&S response to the scene of a crash. Originality/value: This research makes a unique contribution, as it considers traffic incidents not as a single entity but rather as a number of dispatch categories which has practical implications for those emergency medical services dispatching ambulances to the scene.