The NEW Bell Citi has a spot for the light !Great helmet IMO and one a the PBSF on my seat post would be useless my trunk bag covers that area . SO I have one on my rear rack and one on my helmet . Cars seem to give me a wide birth even in daylight hours except for the odd jerk now and then !
My wife has gotten behind me in the car and says in HER opinion the one on my helmet shows up the best even when your looking around . just my 2 cents if its worth that !!