It probably depends on your surrounding environment (i.e. the contrast of the background when someone looks at you). Construction workers along streets and roadways…generally in urban settings with buildings, and less vegetation around…wear safety yellow garments (as dictated by OSHA I guess). But hunters, who are in the woods surrounded by vegetation, wear the blaze orange (not sure if OSHA mandates that). So…if you’re riding on the streets and roadways…I guess go with the yellow. If you’re off-road riding through the woods…go with the orange. And the light as suggested above.
Dan