The only blinkie that will not get washed out would be a fenix light running in strobe mode.. If this is all you are going to use it for, I would buy an L1D, since it is small and uses 1-aa battery.. could also be used as a light in a pinch..
https://www.fenix-store.com/product_...28f43d1e4bd603
I would also consider getting a helmet light for more directional and being seen lighting..