Costa County, California Sheriffs Department conventional two-way radio dispatch channels showed an average of around 2,500 push-to-talk presses per day. The count was within +/-350 a day across all four primary dispatch channels. Telephone A method used for telephone traffic analysis may fit some circumstances. One evaluation looked at 1) peak of busy hour usage, 2) average hourly usage, 3) message length in seconds, 4) maximum delay or wait time desirable, and; 5) maximum percent of users being delayed. Traffic analysis can be applied to radio or telephone communications. Most office telephone systems have some facility for recording calling volumes, and incoming call timing. Dispatch centers use Automatic call distribution (ACD) groups which can be evaluated for metrics such as average wait time, abandoned calls, and calls per hour. These numeric data can be entered into spreadsheets for analysis of trends. In dispatching, US emergency medical services literature suggests that telephone calls to a dispatching facility should be answered in the first few rings. One document suggests emergency calls to dispatch should result in busy signals once per 100 calls during the busiest hour. In business call centers, similar standards are suggested by consultants in order to provide an ideal customer experience and to outperform competing services. Sufficient staffing should be in place so that 90% of emergency calls are, "...answered within 10 seconds, or with no greater than three rings, during the average busy hour," according to one source. Tolerable wait times vary from one culture and region to another: some cultures expect immediate service; others will tolerate waits for some services. Regardless of sector or industry, almost all dispatchers will spend virtually their entire work day on the phone, answering as many as a thousand calls in a single shift while multi tasking other aspects of the job. In many ways, being a dispatcher is really one person doing the work of three or four people. It consistently ranks as among the most stressful jobs in the industrialized world, with high blood pressure, fatigue, obesity, heart disease, and other stress/sedentary related health concerns existing at rates up to ten times the norm of any other occupation. Zone system to assign service calls One method for organizing assignments in a manual dispatch system is to use a zone map system. Consider a community with four fire stations and two ambulance service providers. A grid is overlaid on a community