( above )....a photo taken in a city environment between tall buildings ( heavily shaded ) is not what people mean by normal daylight. Like was said before a camera photo can't represent what the eye sees. If you doubt this look at the red traffic lights in the distance. These types of lights are thousands of lumen but in the photo you barely notice them. Viewed in person the traffic lights would be very bright. If you were going to use a rear lamp in this type of daytime city environment ( heavy urban traffic with short lines of sight ), I would think something like the Red Zone 8 ( or another lamp that is super bright with a wide output ) mounted to the back of the helmet would be the most useful.