This question comes up frequently: "Should I install one of those kits that allows the use of directionals as brake lights?"  In the absence of scientific evidence or studies on how vehicles react to different types of brake lights, here's my opinion; a response sent to a wBW visitor...

Note: One of these days, we may get around to reviewing this type of product (see the Kisan Tailblazer) ...in the meantime, here's an opinion.

The topic of signal lights being used as brake lights comes up pretty frequently on many of the email lists I receive. It's my understanding that the consensus is that it's illegal in most states, but as you've found, the laws are pretty obscure in this area, so it pretty much depends on how the local law enforcement officer feels about it.

The other issue is -- are following cars going to recognize that a directional that comes on means the same thing as a brake light? There is some question as to whether or not the lighting of turn signals as brake lights would take a following vehicle's attention and focus off the actual brake light itself, even for a moment, and confuse them, which could increase their stopping distance. Who knows -- it's all pretty theoretical, and I sure wish someone would conduct a scientific study on how other drivers respond to lighting.

My personal feeling is that it's better to concentrate as much stop light power as close together as possible. When I follow motorcycles, I notice that bikes invariably have really bad tailight/brakelight visibility. Some are really terrible. And during the daylight, many motorcycle brake/tail lights get very washed out in the sunshine.

Many bikes use an 1157 bulb, which burns as a taillight and then burns brighter as a brake light. I think this is bad -- there should always be a separate red light that comes on as a brake light; my feeling is that bikes (and cars!) should always have "one bulb, one use"; i.e., it's better to have a dedicated light that goes from not on to red, rather than use a light to do more than one thing. This can be done via rewiring on many bikes. 

The other thing I use is a Signal Dynamics-type LED brake light bar placed as close to the stock brake light as possible; there are many different types of LED's or standard red lights that can be easily wired in to the brake light circuit. The idea is to get a really, really bright red light that comes on in a single location when you're stopping, so that there's no confusion about what you're doing and also so it draws the following driver's attention to the area on the rear of your bike that means "stop".

Anyway, that's my .02!  

As always, thanks for visiting webBikeWorld.....