get some to play around with, sounds silly but make a card mock up of the corner of the bumper with a carard sticking off, cut and mount them into the card, and run it off a battery. take it out and place it near the bumper at night and it will give you an idea of looks, light dispersion etc, and what peopel can and can';t see at that angle. if its hidden it might work.
but i think the placement asthetically is out. would need to see a pic of the car with canards on.