before i forget
This is something from the book that was not explained in the movie. (well, there was one throw away line that was easily missed) there is a moat between ground level in the T-rex paddock, and the fence. This exists to discourage the dinos from getting close to the fence.
It is this moat that the car is pushed into. There is a section of the book that deals with Grant trying to figure out how to climb out of this moat with Tim and Lex (the T-rex simply steps over it)
There were only six divisions on the whole island. And each division was separated from the road by a concrete moat.
...
"You know," Ellie said, "some of these dimensions are enormous. Look at this. This concrete moat is thirty feet wide. That's like a military fortification."
...
"Absolutely not," Arnold said. "These are expensive animals, Mr. Gennaro. We take very good care of them. We maintain multiple barriers. First, the moats." He pressed a button, and the board lit up with a network of orange bars. "These moats are never less than twelve feet deep, and water-filled. For bigger animals the moats may be thirty feet deep.
@ that ‘hope for the best but expect the worst’ line.
