St. Mary's County the Volunteer Squads are not self insured, the have insurance through an insurance company just like everyone else. Can't speak for Charles or Calvert, but each company in St. Mary's buys it's own insurance and is not self insured.
Cosmetically, there doesn't appear to be much damage to the Ambulance, no word yet on frame damage, but according to the out of service listing on the radios last night at 1900, the Ambulance is out of service.
I currently have a 2016 F-250 4x4 Crew Cab with the diesel, with 40k miles on it, and can say it is a great truck! It tows like a dream! I have only had to do routine maintenance on it since I bought it.
Pros of a diesel:
Yes, they do last longer
Fuel economy (a recent trip to Florida...