All the way back in 1907, the American Medical Association published this editorial in their journal.

Key Quotes:

"One feature of the accounts of ambulance accidents is that in the majority of cases the ailment of the sufferer who is being taken to the hospital is not such as demands speed to save either life or suffering."

"The rushing across avenues crowded with traffic should never be permitted except under the most urgent conditions, and those absolutely known beforehand and not merely presumed on general principles."

"… a reduction in the number of accidents to ambulances must come rather from stringent enforcement of certain precautionary regulations rather than from renewed efforts to have the right of way…"

"It is needless to remark that such stringent regulations should be enforced with regard to ambulance service as will lessen the number of accidents."

Highlights - JAMA Editorial 1907.pdf