Where by "from a distance" I actually mean "drove past it one lane away", because the traffic was still doing that. I felt no need for intervention because the occupants of the car were standing a short distance away watching it and looking distressed, and the police were there and the fire department's sirens were audible.

As we approached, it was a car stopped and smoking. As we passed, it was a car engulfed in flames. So yes. REALLY FUCKING QUICKLY with the spreading.