The ground ambulance Emergency Response Zones are defined by ambulance call and population density. The two zones that comprise the Exclusive Operating Area are distinguished by response times and each zone is applied to multiple areas of the County, which may not be contiguous. The new zones are designated as High Call Density and Low Call Density. See the Emergency Response Zone map below.
Priority Response Levels
Priority 1 - Potentially Life Threatening Emergency Response
Priority 4 - Interfacility and Non-Emergency Transports
Priority 5 - Critical Care Transports
"Response Times" are a combination of dispatch, operations, and field operations. The Response Time for a call for ambulance service is the elapsed time between when the call for service was received at the EMS Dispatch Center until a transport-capable ground ambulance arrives at the scene. Response time compliance is to be maintained on 90% of all calls and is measured monthly. See the Response Time Compliance Requirement chart below.
Response Time Compliance Requirements
High Call Density (A)
Low Call Density (B)
+/- 15 minutes (scheduled) or ≤ 59:59 minutes
+/- 15 minutes (scheduled) or ≤ 89:59 minutes
Response Time Compliance Oversight
A primary function of the Merced County EMS Agency is the oversight of the performance-based ground ambulance contract. Sierra Medical Services Alliance (SEMSA) is the exclusive provider of ground ambulance transport services for Merced County. As part of the contract oversight process, the EMS Agency generates a monthly "Response and Transport Summary" report that provides a snapshot of that month’s ground ambulance response and transport activities. See the monthly Response and Transport Summary reports located in the table below.
Priority 1-4 Monthly
Priority 5 Quarterly
Jan Feb Mar
Apr May Jun
Jul Aug Sept
Oct Nov Dec
Response Time Compliance Review Process
The Provider Compliance Forum (PCF) is made up of various local EMS participants and meets on a bi-monthly basis. PCF is an open forum where ground ambulance response times are reviewed and comments and suggestions are made to the EMS Agency. For more information about the Provider Compliance Forum, or if you would like to be placed on the PCF mailing list, please phone the Merced County EMS Agency at (209) 381-1250.