When you are in a motor vehicle ANYTHING/Anyone that would be something/someone you would not want to hit or run over would ( or could ) indeed be called a hazard. There are many types of hazards, some very dangerous some not as dangerous. As such different consequences occur for failure to avoid the different types. Now from the cyclist's perspective it's the motor traffic that presents itself as the hazard. Used as an adjective you could say, "When a cyclist rides on the road at night without a light he creates a hazardous situation". Or...in a sentence like this, "The driver was weaving so severely that he was a hazard to everyone on the road". Summing up, all depends on your point of view as to who or what is a hazard or conversely who or what is hazardous.

If you call a person riding a bike, "traffic" , while correct in the lesser sense of the word the more colloquial use of the word would define traffic more precisely as "motorized traffic". Hence, if the announcer on a radio station tells you that, "... Traffic is back-upped on the Parkway", rest assured, he isn't talking about anyone on a bicycle. English is an interesting and versatile language. As such it pays not to fret too much over definitions. Of course if you go into court and tell a judge that you didn't consider the guy on the bike using an amber light to be a hazard ( thus causing him to get hurt ), lets just say I wouldn't want to be in your shoes.

Once again, amber is just a color that is used for many things. The main idea being, "It is used to attract attention" Of the amber lights I've seen, it seems to get the job done, whether on a moving vehicle, a cyclist or a stationary object.