Estimating the effect of traffic calming measures on ambulances

Objective: To estimate the effect of traffic calming measures (TCMs) on ambulance response times during different types of service (emergency and nonemergency transfers, with and without a patient), in different traffic conditions (free flow or forced flow), and over entrance ramps with different slopes. Methods: Two ambulances equipped with global positioning system devices were monitored for 2 weeks to study routes and speeds. To assess the influence of TCMs, speed of the ambulances over the TCMs, seconds of delay, and total time we calculated. Results: Ambulances changed routes by more than 1 km to avoid TCMs if patients were inside, leading to delays of up to 40 seconds. Average speed over TCMs differed in relation to traffic conditions (P=.045) and type of service (P=.001). Each TCM contributed a delay of between 1.4 and 4.3 seconds, depending on type of service and traffic conditions. Conclusions: Response time was influenced by the presence of TCMs. A mathematical model that predicts response time by taking into account the number of TCMs can help ambulance services select the most appropriate route to drive.