The National Fire Protection Association is an international organization that publishes standards related to fire safety as well as rescue services provided by emergency services. They publish a standard, NFPA 1710, which outlines emergency response time goals. Unfortunately, the only places I can find the actual standard requires membership in the NFPA to view it.
I have, however, been able to find summaries. In this summary you can see Emergency Medical Services (EMTs, Paramedics) are expected to leave the station within one minute of a call being dispatched. Note that being dispatched isn't the time from when one initially calls emergency services; it is the time from when emergency services is able to determine what is needed and issue the dispatch request. This article describes how fire and rescue organizations differ in how they measure responsiveness including identifying how some organizations start measuring response time at the point a call is first received.
First arrival on scene for EMS is targeted at four minutes after "turnout," when EMS is dispatched. EMS treatment levels include:
- First responder (includes provisioning of an Automatic External
- Basic Life Support (BLS)
- Advanced Life Support (ALS)
Note that this standard is based on how quickly life sustaining measures can be delivered to the person or people who need them. Transportation times to hospitals will depend on the specific transportation protocols that will be implemented once EMS has assessed the situation.
The State of Maryland, as an example, manages protocols through the Institute for Emergency Medical Services Systems (MIEMSS). Their current protocol is available for reading. On page 17, one of the steps EMS has to determine is the "mode of transportation."
Maryland's protocols highlight that transportation isn't to the closest hospital but, rather, to the closest appropriate hospital. The closest appropriate hospital is determined by EMS in consultation with their support system. The protocols and infrastructure that Maryland has put in place are designed to get the patient stabilized and to the most appropriate treatment facility based on the patient's need.
The NFPA is a recommended code and it is up to each state or local governing body to determine if and how they will implement them.
For the State of Maryland, the MIEMSS is an independent state agency appointed by the Governor.