I once stopped to assist at a car fire - tire on the ground was aflame (probably had been run flat for quite a while). I had an extinguisher, as did other bystanders, but the fire kept reigniting after momentary knockdowns from various extinguishers.

Finally resolved when someone dumped water on the hot rim, reducing the residual heat.

Years ago, the Fed Gov't concluded that carrying fire extinguishers in fleet vehicles was not cost effective....FWIW