I think one of the issues is you are in a bus and seated much higher than the white car. So from an angle perspective, while you are theoretically close enough to see the plate, you are looking down on it at an angle which makes it hard to read. If you were in a passenger car and your cam were mounted lower the view of the plate might have been better. Maybe you can consider repositioning the camera to 3/4's up from the base of the windshield if that is legal in your state and does not interfere with your field or vision or distract your driving.
