[throw0101b]

> These cyclists unfortunately need to just point their headlight downward […]

On well-lit urban streets, you probably don't need more than ~500 lumens, as the road is already illuminated and the light is mostly about other people seeing you.

Also, having it flash in a consistent manner (and not some kind of "random" cycle) is best, as it's easier to track a simple on-off pattern with a deterministic frequency.

(If you're riding on non-lit roads or trails, then certainly more lumens and further throw is useful.)