Commuting 101: Lights at night

Lights have come a long way since I started bike commuting over 20 years ago. In the mid-80s, I used a 6 watt dynamo to power my incandescent headlight and tail lights, supplementing those with the old flashing yellow “Belt Beacon.” Today, a dizzying array of lighting choices are available for the night cyclist. You can still buy halogen lights, but they might be powered by a hub generator, bottle dynamo, or batteries. I strongly recommend rechargeable batteries, but even here a number of technologies are available: sealed lead acid (SLA), nickel metal hydride (NiMH), lithium ion (Li-ion) and nickel cadmium (NiCad). SLA are cheap but very heavy; Li-ion are pricey but light; NiCad are inexpensive; and NiMH are moderately priced and fairly lightweight and reliable.


Front lights are typically divided into “be seen” and “to see” lights. “Be seen” lights are the little blinkies. “To see” lights are those that provide a steady beam to light up the road or trail in front of you. Blinkies are appropriate only for well lit urban areas. For night riding, I like having two lights — one set to blink or flash, the other set to a solid beam. The faster you ride, the brighter your light needs to be.

Halogen, LED or HID?

While halogen is still a viable option today, the current crop of ultrabright white LED lamps can outshine the 10 watt halogens and rival 20 watt halogens in brightness. While they’re pricey, the higher efficiency of LED lighting translates into longer night-time riding. Off-road bikers like the piercing light created by High Intensity Discharge (HID) lamps, but these lamps tend to be very pricey.

Watts and lumens quick and dirty

Lamp brightness is measured in lumens and candelas, but lights are normally marketed in terms of watts. Lens and housing design plays a tremendous part in how focused the beam is on the road — a 3W dynamo-powered light can outshine a 10W halogen, for example. But to keep things simple (perhaps too simple) here are some comparisons:

  • The brighter “blinkie” style front LED lamps put out less than 20 lumens.
  • Each typical 55 watt halogen car headlight generates around 700 lumens on the low beam.
  • 6V 3W halogen bulbs are used in dynamo powered incandescent lights.
  • 12V 10W and 20W halogens are very bright bicycle lights. 10W halogens put out about 200 lumens, while 20W halogens generate 400 lumens. I have an older 10W + 20W halogen system with SLA battery for a combined 600 lumens of light which is almost at the level of a single car headlight. I’ve had people tell me they thought I was a motorcycle with this light.
  • My 2 x 3W Princeton Tek Switchback bicycle light puts out 170 lumen, which is about equivalent to the light from a single 10W halogen but with much less current drain. With 6 watts of LED lighting, I’m comfortable riding along at up to 20 mph. While I don’t think I’ll be confused with a motorcycle, the blue-white LED is distinctive and identifies me as a cyclist.

Tail lights

These are the red blinking lights, and almost all of them today are red LEDs. Bigger is better, in my opinion. I really like the Cateye LD1000. This rear light, incidentally, also provides good side lighting which I consider to be almost as important as front and rear lighting.

Smaller red LED tail lights are often times almost invisible. For tail lights, I think surface area of the lens plays a large (ha ha!) role in the visibility of the lamp.

Another factor to keep in mind is battery life. The manufacturers all claim dozens of even hundreds of hours of battery life are possible with their LED blinkies. While the light does continue to operate, the light output is often so dim that the light is almost invisible in traffic conditions. Remember, your little light is competing with bright lights from cars, trucks, motorcycles, signal lights, street lamps, and illuminated business signs. Seen through the haze of a filthy and gravel-pitted windshield, your little light gets lost. It’s a good idea to recharge your batteries at least weekly.

Supplemental lighting

Hokey Spokes attach to the wheel spokes and can be programmed to created images and text as the wheels rotate. I’ve seen them in action and they’re really cool. In in urban environment, I don’t know if they add enough light to overcome the usual lighting from cars and business signage.

My goal at night is to look like a construction barrier or something else that would be painful to hit. When I lived in snow country, I aimed to look like a snow plow at night. To this end, I use a yellow Lightman xenon strobe that I strap to the back of my messenger bag. This is a xenon strobe, the same kind of electronic strobe used for camera flashes and dance lighting. I like the Lightman strobe because it’s fairly lightweight, comes with a number of mounting options, and is very sturdy. Xenon strobes eat batteries quickly, so rechargeable is highly recommended.

I’m also a believer in passive reflectors. I use reflective ankle straps and put reflective tape on my helmets, on my frame, and on my bags. My commuter bikes have the CPSC spoke reflectors.

Other factors

When equipping your bike with lights, some other factors to consider include

  • Mounting options: will they work with your oversized handlebars or oddly placed stays?
  • Water resistance: Even the ones that claim to be weatherproof aren’t necessarily after a month of continuously, daily usage in the rain and snow.
  • Button exposure: Depending on how you mount your light, consider how the buttons might be pressed. For example, the button on the Cateye LD500 is difficult to press when the light is mounted on my Blackburn rack. The buttons on the side of the LD1000, on the other hand, are too easy to accidentally push, meaning a discharged battery at the end of the day if the light comes on after leaning your bike against a wall.
  • Construction: I’m brutal with my gear, but the only lights I’ve had any real problems with are the (no longer sold) Serfas WhiteLED and RedLED. They’re great looking lights and very bright, but they’re also cheap junk that don’t last longer than a single season of use.

When I visit Interbike in two weeks I hope to review as many lights as possible. I know we have some Dinotte fans here. What kinds of lights do you like, and what should we avoid?

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