On rainy days we may blog about equipment and the rationale of selection.
As the hours of daylight dwindle to a precious few, bicycle lights are more important than ever. Rear lights are important because you're relying on them for cars you're not looking at; you're unlikely to steer your way out of a overtaking-car collision, even thought they're not the majority of night time car-bike accidents. I'm using two rear lights, a Cateye TL-LD1100 and a PDW Radbot1000, and I think they make a good team.
One of the primary decisions about lighting, front or rear, is power supply; where do the electrons come from? The "serious cyclist" answer is a front-wheel hub dynamo powering the lights, but the range of lights you can use is limited (there are some recent developments that offer increased choices). The "green-commuter" answer is rechargeable batteries, often built into the device, that (increasingly) use USB connections to recharge; this often involves removing the lights for charging. The "Fred" answer, and the choice I ended up making, is AA and AAA batteries, which can be purchased at most convenience stores; these present an ongoing expense and an environmental impact.
I've added a Radbot 1000 to my rear light array in the last year because it's one of the best lights in a new category: the LED strobe. The Radbot1000 from Portland Design Words is passive-aggressive; it's a combo passive reflector and an extremely bright, occulting strobe light. It's annoyingly bright and suitable for daytime use. It uses two AAA batteries and the mounting clip is compatible with the mount from the PlanetBike SuperFlash, which is its primary competitor.
My other rear bike light, and my mainstay rear light for a decade, has been the Cateye TL-LD1000 which used two AA batteries. This light contains 10 LEDs, in two rows, wrapped across three surfaces of the light - in other words, two LEDs facing left, six facing the rear, and two LEDs facing right. It's an excellent, sturdy reliable rear light.
In the last year, my TL-LD1000s (I have one on two different bikes) have become problematic: when they get bumped around they turn themselves off. I suspect the battery springs lost their tension. I sent Cateye an email a few weeks ago, they sent back a reply asking me to ship them the two TL-LD1000s, and the mailman just delivered a package containing two of Cateye's most recent offering, the Cateye TL-LD1100.
There are a few upgrades in the 1100 version: the overall design is the same, but the LEDs are twice the brightness of the 1000, the battery sleeves seem to provide for easier replacement, and the case locking mechanism seems more robust. I'm very impressed that Cateye replaced two 10-year old lights with an upgraded model gratis, no questions asked. It makes me feel better about buying another Cateye light the next time I'm shopping.