Please get a friend with a videocamera the next time you have to be in a pick up the girls situation. Tell the friend to lay low.. and if he is doing this type of thing again, get it on camera.
Eventually, even if he is found violent, he probably will have them again for visitation. So never pick up alone if you can get a friend to go.
Yes, call your attorney he will probably get you a restraining order and custody.
No kids should ever be locked in a car.