In life-threatening emergency situations in which every second counts, the timely arrival of an ambulance can make the difference between survival and death. In practice, the response-time targets, defined as the maximum time between the moment an incoming emergency call is received the moment when onsite medical aid is provided, are often not met. A promising means to reduce late arrivals by ambulances is to proactively relocate ambulances to ensure good coverage by the available ambulances in real time. This paper evaluates two dynamic relocation policies that an ambulance service provider in the Netherlands modified for operational use and implemented in a software tool for realtime decision support. The policies were used in a pilot program within a dispatch center for 12 weeks. Based on the success of this pilot, our policies were adopted for ongoing use and permanent implementation. This paper describes the relocation methods, evaluates the pilot, provides statistics for efficiency improvements, and discusses the experiences of ambulance dispatchers and management.