Your flashing amber light (or pair of them, one left and one right) may be more visible than you think even if it is not nearly as bright as your headlight.

While driving home this evening I compared the headlights vs much less bright non-flashing turn signals of oncoming cars. The non-flashing amber turn signal lights were barely noticeable on a surprising number of such cars. Yet I am quite certain almost all of them are quite visible when flashing at a constant rate. (Edit: These bulbs have two filaments and do increase in brightness when turning, but still much less light than the white headlights).

The ability to detect a small, regularly fluctuating signal near or mixed with a large signal has many other examples. For example, in recent years astronomers are detecting the presence of planets orbiting stars located light-years away by detecting the tiny fluctuation in the star's light as the planet passes between the star and earth.