I live in a major metropolitan area, close to a lot of excellent hospitals. I know of three locations, less then a mile from my house, where ambulances and ambulance crews are on call to go out in emergencies. The night my daughter was born, I called 911 because I was hemorrhaging (placenta previa) It was twenty minutes before an ambulance arrived at my door. All three of those crews I knew about were already out on calls.
The rural women you talk about, who have a lot of kids and are likely to give birth on the way to a distant hospital, are a classic case for "convenience" inductions, which allow them to arrange childcare in advance and arrive at the hospital before they go into labor. While there are risks to induction, there's also a need to balance those against the risks of birthing unattended, or in a situation where help may take significant amounts of time to arrive. That risk is even greater if there's only one ambulance in a community (not unusual in rural areas). Usual response time is meaningless if the crew already has a patient in the truck.
Also keep in mind that statistical response times published for 911 services don't all have the meaning you seem to expect. Around here "911 response time" means the length of time it takes to get off hold and actually speak to an operator.
Edited by MeepyCat - 7/8/13 at 3:14pm