Check state laws first. In this state a bicycle using a blue light is illegal.
Yes, that's a concern as well, hence the green light idea. I don't want to beat a dead horse but think about a stopped school bus. Red flashing lights, the sign swung out, etc. Given all that how many times have you seen a car drive right past? I have, a number of times. Heck, I almost did it twice in my years of driving. Both times my mind was wondering off about something else and not paying 100% attention to the road. Whenever there is something odd, something different I almost always take a second or third look. That's what I'm after. Something that is different that makes a motorist look twice.