To make it turn like a vehicle required a completely different approach because it was too hard to place the directioner/trigger objects. Knowing the angle to the next point didn't work because a vehicle requires space to turn around - and the amount of space varies depending on the approaching angle and where the next point is in relation to the current point.
I tried path finding (like dop suggested) but couldn't get that looking accurate either - when it rotated it didn't look like a truck turning (looked like a tank).
so I changed the trigger objects to know which trigger is the next one to head to, and then the patrol truck keeps turning towards the next point until it is lined up with it (using a pointer object to tell it how far off the angle is and limiting how much it can turn each tick).
this method works really well and looks like a vehicle to me. I wasn't sure what you meant by changing the animation when the angle changes - do you mean some kind of 3d or 2.5d effect? And I also didn't understand what you meant by reverse and change path. do you mean coming to a stop, backing up and turning down a different road? That is a much more complicated AI, and you would have to define the rules of your world to know what would make the vehicle stop and choose a new route. My method is still using bullet behavior - and bullets don't go backwards...