A lumen is a measurement of how much light a source emits. It takes into account the sensitivity to the human eye to the wavelengths emitted. So it’s a pretty good indication of how bight something will look. But what you really need to know is that every version of See.Sense. is brighter than the car lights you see on the road every day. This enables it to stand out against traffic signals and the lights on other road users, like cars and trucks.