I don't know what caused this accident but it brings to mind the possibility of "Tanker Slosh"
Tankers may have baffles and different compartments to help stabilize their liquid load but just like loads shifting in an earlier post cargo that is in motion will tend to remain in motion.
If the driver makes an emergency move, the liquid may slosh about in the tank causing the driver to momentarily or totally lose control of the vehicle.
In the case of a tanker exiting a highway, if a car slowed quickly in front of this truck and he hit his breaks too quickly, half a second later the truck will lunge forward from the inertia of the liquid as it surges forward in tanks. If the truck is turning at a speed as on an exit ramp, that inertia could try to keep the truck going straight, and in this case it was straight into the ditch.
Whatever the cause, I suspect this driver may have been exiting a little too fast for the curve he was in.
Need I mention to leave lots of room for trucks especially if they are carrying gasoline and never brake hard in front of a truck, he may not be able to stop.
More on road safety at http://www.ezee.ca
Forklift Safety at liftright.net
See Truck photos or my other photos at donssite.com
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