Do warning lights and sirens reduce ambulance response times

Objective. To determine the time saving associated with lights and siren (L&S) use during emergency response in an urban EMS system. Methods. This prospective study evaluated ambulance response times from the location at time of dispatch to the scene of an emergency in an urban area. A control group of responses using L&S was compared with an experimental group that did not use L&S. An observer was assigned to ride along with ambulance crews and record actual times for all L&S responses. At a later date, an observer and an off-duty paramedic in an identical ambulance retraced the route—at the same time of day on the same day of the week—without using L&S and recorded the travel time. Response times for the two groups were compared using paired t-test. Results. The 32 responses with L&S averaged 105.8 seconds (1 minute, 46 seconds) faster than those without (95% confidence interval: 60.2 to 151.5 seconds, p = 0.0001). The time difference ranged from 425 seconds (7 minutes, 5 seconds) faster with L&S to 210...