I got to disagree. I don't see support legs, there is a gray steel upside down U-shaped thing next to the truck (photo 3) but if you look real close at photos 4 & 5, the bar is still there. The truck didn't have support legs, you can see the bottom of the truck while it's laying in the water. There are no legs. If there were legs, the frame of the truck wouldn't be twisting so badly before it fell in.
It's a european thing. Roads, cars, parking spots are much smaller overseas and they simply can't "tow" a vehicle. When your car is parked illegally and needs to be towed they can't get in front of it since the majority of the spots are parallel parking spots. Also most of the cars are manuals, so everyone uses a parking brake. What they do is reach over, grab the car, throw it on the flat bed and drive away. I've never actually witnessed it, but the guys have told me it barely slows down traffic they do it so quickly.
If you look at the truck in the water, you can see the tilt bed. His boom is extended pretty far and he isn't as close to the edge as he should be. If you look at the boom angle relative to the truck, when the car clears the water (photo 2) the boom is very low and probably getting reeled in with the cable. When the car is up in the air (photo 3) the boom is much higher. The combined wet weight of the car, max extension on the boom and shifting water inside the car probably did him in.
It Doesn't take an Idiot to be a Brain Surgeon