Yesterday I rolled up to the first spot in the right lane of a busy
intersection near the interstate. I was in my westy. I saw a guy get
out of a huge seventies sled that had died in traffic and stick a
cell phone to his ear and walk through busy traffic to a gas station
nearby. Unbeknownst to him, the car, which had been smoking lighly
from under the hood, started smoking a lot and dropping what looked
like burning chunks of plastic or rubber onto the road beneath the
engine compartment. The thing was thirty feet away. Black smoke was
really billowing a few seconds later. I pulled my westy onto a
concrete turn island and ran out the side door with the fire
extinguisher. The wind was so high that I had to get nearly behind
the car to make the spray hit the fire. By the time I got the aim
right in the high winds, the fire extinquisher was nearly out. I was
standing hear the gas tank, where I didn't want to be, and the fire
was out, and the burnt wired shorted and the car tried to start
itself again, so I ran back to the westy and climbed in and waited
for the light to change. And waited and waited. The fire started up
again. I waited and waited. I was afraid that all the surrounding
cars and mine too would be blown to smithereens when the gas tank
lit.It puts a different perspective on waiting when you think by
staying you could get killed or burned, it's not like waiting in line
at the store behind someone who has an envelope full of coupons and a
bunch of stuff that won't scan. I waited and waited and waited some
more. I wanted to run the light but there was too much traffic.
Nobody else had a fire extinguisher, though a few had gotten out of
their cars but were afraid to get close. I waited and waited  and
then the light turned green and I shot out of there like a slug out
of hell (it's a diesel).
.

The moral of the story: one extinguisher won't do it, and nobody else
has one, so carry two.

Jim