I've just started bike commuting, half of which is after dark on roads with few streetlights. I went with a 250 lumen nightrider 250 wireless for the front. People can definitely see me as cars and even dump trucks on side streets have given me the right of way from 100 feet. However, road surface visibility is not spectacular and I find myself slowing down quite a bit in some sections. I would say if youll be anywhere where your headlight is your only source of light spend more than I did which was 120. Other than that I've got a hi vis vest, and ankle/wrist reflectors and reflective tape covering the majority of my bike. Makes me feel pretty safe.