Response time of emergency vehicles may be predicted using ordinary gps estimates

INTRODUCTION: In a multiple-tier prehospital emergency system, knowing the response time of supplemental prehospital units may aid the ambulance personnel in deciding whether to remain at the scene and initiate treatment or to load the patient and head towards the hospital. We sought to correlate the actual to the predicted response time indicated at the GPS display in the vehicles of the supplemental prehospital resources. METHODS: From December 2016 to February 2017, all emergency runs with lights and sirens performed by the mobile emergency care units in Odense were registered. For each emergency run, the physician registered the actual response time, the distance to the incident when travelling along the route suggested by the GPS and the predicted time to arrival. These registrations of time variables served as the basis for a linear regression analysis. A correlation between estimated and actual response time was calculated. RESULTS: A total of 617 runs were registered. In all, 189 runs were excluded. Thus, a total of 428 runs were included. We found a linear correlation between the GPS-predicted response time and the actual response time, which may be described by the following equation: y = 0.88 + 0.58x (R² = 0.90; p < 0.0001). CONCLUSIONS: We found a linear correlation between the GPS-estimated transport time and the actual response time. We propose a practical model in which the actual transport times can be predicted by multiplying the GPS-estimated transport time by 0.6 and adding 1 min.