Advantages to plopping emergency services on an isolated road?

The initial cost (especially in the early game) and more importantly the hourly cost of emergency services seems to highly suggest that less is more, especially when starting to build the second-tier buildings (hospital, precinct, etc.). In comparison to Sim City 4, it was quite easy to plop services frequently enough to where their coverage zone covered the entire map, but this is not so (at least for me) in this rendition. The cost of the hospital seems to suggest that one should be enough for the entire city (village), yet I still have health issues. Of course, traffic has a big influence on this, but even when my traffic isn't terrible, health issues remain (even in R & C only cities).

I've been experimenting with building an isolated road that attempts to be unattractive for all civilian traffic, and then plopping all of my services on that road. This, at the very least, allows the vehicles to initially get on the road easier vs. coming out into a traffic jam when the services are placed in a central location. However, the downside is that the services are a little further away than they otherwise would be.

Has anyone experimented with optimal emergency services placement? Certainly the goal is to maximize coverage with as few standalone buildings as possible.

The answer is in the UI really.

I have had this same problem before with my own cities and have found that plopping your services down in a centralized area that covers most of the roads (indicated by the green catchment area) is the best method.

Throughout Simcity the main problems you will face are often sorted/negated through proper road planning and the effective placement of buildings.

Your theory does indeed work if the isolated road runs through a built up area, good connections to this road will help ease traffic from the rest of your city and ensure that emergency vehicles don't get caught in heavy traffic. This gives you the best of both worlds; a nice steady (clear) road with great traffic flow and coverage of nearby areas.