That is, the people driving a police car, fire truck or ambulance might have no training in how to do so properly, despite the (not unreasonable) expectation from the public that they'll perform better and the legal difference in how they are treated when doing so. Some employers might do better, but there's no universal standard.
The results are predictable, excess death and injuries as a result of giving inadequately trained individuals a relatively heavier, more powerful vehicle.
The only reasons we generally transport "priority" (lights/sirens) is for unstable patients or time critical: acute cardiac or respiratory issues, stroke, hemorrhagic or multi-system trauma, or shock.
But even patients presenting stable can deteriote en route.
As an aside, generally, in most areas, what makes the biggest difference to getting a patient to definitive care in a timely manner is not lights/sirens, nor speed, it's "Opticom" (also known as traffic light pre-empting). Visual (strobe), or occasionally radio that communicates with traffic lights to give us a steady flow of green lights. That coupled with people moving over is the big difference. Speed is just an increased liability (fun fact, most state laws grant emergency vehicle drivers the ability to 'disregard' any road law while operating in any emergency mode, but that comes with a "presumptively at-fault" for any incident that occurs in that mode, i.e. you will be considered at fault unless there's evidence to the contrary).
If you have a siren on your truck, you are government was my thinking. These are all "public goods" and even as a kid with minimal "civics" education (and what I had was pretty much 100% Pro Usa America Is A Christian Nation for those formative years that I'm talking about).
I understood that as a basic. Nobody told me that "no, actually. Despite having sirens, ambulances are not (usually) driven by workers for the government." It wasn't til I lived on my own that I really understood that.