First 'good' is relative. For many the Planet Bike Superflash or Princeton Tec Swerve, and others of the type are 'good' enough. Some have upped the ante to the Dinotte or Klite tailights.
Here is a video taken in daylight with three Superflashes. One steady two flashing, one of the flashing ones on the back of the helmet (Camera Sony Digital 8 Handicam):
<embed src="http://img515.imageshack.us/flvplaye...Msuperflashday" width="640" height="380" allowFullScreen="true" wmode="transparent" type="application/x-shockwave-flash"/>
The darker parking lot pavement is about 50' (15 m) from the camera. This is the distance for cars to the right or left to yield. This is full behind. Side views are less bright.
Cameras are notorious for failing to pick up brief flashes of light if they are out of sync and the flashes are too short a duration. This camera adds a lack of resolution on top of that. So I repeated with all three Superflashes on full and a long duration yellow Xenon strobe behind the Superflashes on the seat stays. I carefully aimed the lights and it is a slightly higher camera position. This is 'everything I got'.
<embed src="http://img714.imageshack.us/flvplaye...superflashday2" width="640" height="380" allowFullScreen="true" wmode="transparent" type="application/x-shockwave-flash"/>
The helmet light was 'On' showing how beamy the Superflash is. Head tipped -not seen from behind, side yes. The lights show better on full. Mostly a camera effect, though the intensity of a flashing light is less on average. We count on the simulated movement of the flash to catch the eye. That works under lower light conditions. Without a high speed vieeo camera, I can't record it. I may have the only Superflashes in town, so I have no visual reference to how they work on bikes as a motorist myself.
Bear in mind I am riding away at under 20 mph (32 kph) the closing speed of a car going about 10 mph over a 30 mph limit (16 kph over a 50 kph limit). I ride roads where the closing speed will be up to 3 times as fast.
I first suspected that my three Superflashes were not doing what I thought they were for me when the addition of an ANSI vest. It has the same 'Limon' color of the Pearl Izumi vests and other clothing but has reflective stripes for night, too. You can see that vest for 1200 feet. Can't identify the bright spot, and will likely ignore it, but you can see it. I got a lot better respect and fewer issues with motorists after adding the vest.
Likely in sun, particularly in low sun, and with an upright or more upright riding position, the clothing is unsurpassed for maximum distance. I suspect we cannot do as well by any legally bright taillight. For cloudy days, shadows of buildings and other day situations where the sun isn't helping light up the clothing as much, I want to see 'brake light bright' lights. Hopefully, such a light shows up even with the sun low and shining on it. The goal is to give motorists on faster speed limit roads more warning time. I won't need that much power at night so two levels would be good. Side visibility to 180 degrees or a bit more.
Troutie allowed me to post these pics to add fuel to the fire (Many Thanks):
"I have had a few requests for a good tail light. 1 red XPE would make a good tail light and they can be run at 700 ma I am not too sure on daytime vis at that power setting.
Some pics: daylight beam shots. (Ha Ha!) (Brian: I leave them in the album for now, anyway)
The sun is just setting in our garden so it is still pretty bright. There are 3 red xpes @ 700ma with no optics in the first two so throwing light everywhere. The next 3 have a experimental botched optic. The last has three Carclo 10415 10 mm eliptical optics on the three xpes.
Here is a video of the 3 red xpes @ 700ma with Carclo 10415 10 mm eliptical optics:"
I would say just 1 red XPE and a 20 mm eliptical optic in a housing with clear sides would be more than enough with Hi 700 ma and low 200 ma for day and night running."
So how good are your lights in the day? Any mods or 'beasts' out there already? Of course the Superflashes 100 hour runtimes on flash with two AAA's will have to go. Pity.
PS: Daytime 'beamshots' from as many angles as you deem fit to take are most welcome. Let's shed a little (or a lot) of (red) light on the problem!