OK people. There have been a grand total of 11 cases in 2.5 years. NHTSA investigates a lots of things. How many regular drivers collided with emergency vehicles in the same time frame?
The FBI has stats on police deaths by type of death. If memory serves correctly slightly more cops were killed in traffic crashes than that.
However, I’m assuming the crashes were quite varied: anything from a driver recklessly fleeing a stop to some drunk crashing into a cop on the highway shoulder. Most likely these deaths didn’t have a systematic pattern to them that could be prevented if only we knew what the root cause was.