Yes I agree with both Richard and Tony...... Lighting up time means,... "when ever lights are required by law". So even in daytime if visibility is poor. ( Although it doesn't seem to apply to quite a lot of drivers on motorways it seems). But by the same token, if your vehicle has old fashioned carbide lamps and the law says they must work! I don't think there can be any degree of illumination requirement. I also agree that from a safety point of view it must be better to have huge bright lights, but there is also an allowance for vehicles to perform the way they were built......Like the little slit lamps on Jeeps for instance.
I try not to ride any of my bikes after lighting up time whether I have a BO mask or not, as the lights are never as good as modern lights. Ron