Bicycle lighting
There are several types of bicycle lights available, each with their own advantages and disadvantages.
Choosing an Appropriate Lighting System
If you want to cycle at low speeds, in familiar areas, with street lights, other ambient lighting, or when there's a full moon on a cloudless night, a low power LED headlight, and a rear LED flasher are sufficient. If you actually want to see obstacles in darker areas, and stand out in heavy traffic, or if you want to travel at higher speeds (>10 mph) you need a more powerful, quartz-halogen front light. The added power comes with the penalties of greater weight, greater expense, and/or shorter run time. If you are doing bicycle touring, or if you don't want to hassle with batteries, you can use dynamo-powered bicycle lights.
LED Systems
Cyclists that ride at night only occasionally generally opt for an inexpensive LED front light and rear LED flasher. Red or yellow LEDs suitable for use as rear lights have been available for many years. Recently, white LEDs which satisfy the requirements for a front light have come on the market. These systems offer long battery life, and are adequate for riding on well-lit streets, but they do not project a very bright beam. The problem with using LEDs for front lights is that the light from multiple LEDs is difficult to collimate into a usable beam. The very high-power LEDs (5W) have a short lifespan due to the excessive heat that they generate, and are very expensive to replace. In short, LED headlights are fine for "being seen," but they are poor in terms of illuminating the road.
Rechargeable Halogen Systems
Most commuters, and most transportational cyclists, choose to use high-power halogen front lights which operate from a NiMH, Lead-Acid, or Li-Ion rechargeable battery. In the rear they use a red LED flasher, which has LEDs pointing both to the back and to the sides. A xenon strobe is another option for a rear light, and these are sold by several manufacturers, but they are more expensive than an LED flasher, consume more power than LEDs, and the bulbs require more frequent replacement.
Advantages of Rechargeable Halogen Systems
- Very bright
- Usually have two lamps, one spot beam, and one flood beam, to illuminate both the road and the periphery
- High-efficiency optics with an integrated reflector matched to the bulb
- Long-life rechargeable battery
- Very reliable
- Quick-release hardware so they can easily be removed from the bicycle to prevent theft
Disadvantages of Rechargeable Halogen Systems
- Relatively heavy battery
- Limited run-time between battery-recharges
- Hassle of being certain to keep batteries charged
- Batteries must be replaced after 500-1000 recharge cycles
Cost for these systems ranges from US$50 to US$200.
Rechargeable H.I.D. Systems
The very best lights for commuter cyclists are HID lights, similar to what are used on some automobiles. These are very efficient, very bright, and very expensive (US$250 and up). Other than the price, they have the same advantages as rechargeable halogen systems.
Dynamo Systems
Dynamo systems have mostly disappeared in North America. However they are still available from a couple of resellers, and there are many cyclists that prefer the self-sufficiency of dynamo powered systems. For bicycle touring, where you do not want to hassle with recharging batteries, dynamos are a good choice. Most dynamos put out only 3W of power, so the lights will not be as powerful as what is available in battery powered systems, but there is no hassle of battery charging, or worries about whether or not you'll make it home before your battery is exhausted. Many cyclists are content with the illumination that a dynamo system provides, especially if they ride only on familiar routes.
Avoid the cheap dynamo powered systems sold in discount stores and drug stores. The good dynamo powered systems come from Europe and Japan, with names such as Busch & Müller (BUMM), Sanyo, Marwi, Axa and Dynosys. Hub dynamos, where the dynamo is inside the front wheel's hub, are made by Schmidt, Shimano, Renak Enparlite and Joule. In the U.S., dynamo lights need to be mail-ordered (or web-ordered), as virtually no bicycle shops still carry them.
Some lamps for dynamo systems have a back-up power source, called a "Stand Light" to provide illumination when the bicycle is not in motion, while other systems can accept an external battery to provide this function. Higher-end dynamo systems have built in over-voltage protection for the lamps, to avoid bulb burnout at high speed or when one of the lights fails (this protection can be found either in the lamp or in the dynamo).
Since a bicycle dynamo cannot generate much power, the optics on the lamps used with dynamo powered systems tend to focus the limited amount of light in a narrow beam that lights up the road directly in front of the bicycle, but not much on the periphery. This is a necessary compromise in the design of dynamo systems.
Advantages of Dynamo Systems
- Always ready to use, without the worry of batteries
- High-efficiency optics that are designed to maximize the available power for the lamp
- Reliable under most conditions
Problems with Dynamo Systems
- Bottle dynamos that rub against the tire rim are noisy, can slip when wet, and wear the sidewall of the tire
- The cheaper dynamo systems do not have stand lights, so when you stop, your lights are off
- Low power lamps that in some cases do not provide sufficient illumination
- Not suitable for very low speed riding because the lamps will not be at full brightness (brightness varies with speed, until the over-voltage protection kicks in)
Dynamo systems range in cost from around $30 for a basic Marwi system, to well over $300 for the highest end system with a 6W dynamo. Hub dynamos are the best option for a dynamo system, but these require that a new wheel be built, adding to the already significant cost of the dynamo. Some commute bicycles now come standard with a hub dynamo and lights, and the added cost is much less than retrofitting an existing bicycle with a hub dynamo.
Rear LED lights
In some countries for rear lights, LED flashers are the norm. In other countries, like Germany, flashing lights are forbidden by law since people tend to underestimate the distance to blinking lights and also it has been found that drunken drivers are attracted by them. LED lights made for those countries don't flash but shine permanantly when switched on. LED backlights made to be powerd by a dynamo usually contain a high capacitance capacitor which powers the LEDs for some minutes when the bicycle is not in motion.
If you want to by an LED flasher be careful to avoid the very low-end flashers sold in discount stores. The best LED flashers will be solidly built, weather-proof, have very bright LEDs, have a solid mounting system, and have LEDs pointing to the sides as well as to the rear. Good LED flashers, with side LEDs, cost around $25-30.
Home-Made Rechargeable Halogen Systems
Many cycle commuters and transportational cyclists build their own lighting systems with easily available lamps, batteries, and chargers. It is a relatively simple task, and a system that is cheaper, and often better, than commercial systems can be constructed in just a few hours by individuals that are reasonably mechanically inclined. Many web sites have detailed instructions, including parts sources (search for: "build bicycle lighting systems" to find these sites). A lighting system is basically a battery, some lamps, and some switches, connected with wire--not rocket science! The biggest challenge is attaching the lamps to the bicycle, but there are many devices available to easily accomplish this task.
Rechargeable Flashlights
There are some high-power flashlights, with rechargeable lithium-ion batteries, that have excellent optics. These are a good alternative to lights that are specifically designed for bicycles, though they are still expensive (US$80). These can be fastened to the bicycle handlebars with a device called a "Lock Block." Look for a flashlight that has an adjustable spot to flood beam. These are sold by police supply stores, under the Streamlight brand.
Reflective materials
Reflective materials, in the form of reflectors, reflective tape, and reflective clothing, are useful in making a cyclist visible to automobiles. Reflectors and reflective tape do not consume any power, and provide additional visibility, especially when applied to moving parts of the bicycle. However they are visible only when in the beam of a headlight, and they do nothing to light up the road. Reflectors are not an adequate substitute for a headlight.
Repairs in the Dark
Carry a flashlight with you while cycling at night. It will help you to make repairs in the dark, if your headlight cannot be removed to illuminate the work area, or if you are using a dynamo powered headlight.
Safety and Legal concerns
Cycling without good lights is very dangerous. Reflectors alone are insufficient, and lights are required by law in some areas. However do not make the mistake of believing that simply meeting the minimum legal requirements for lighting is sufficient. The minimum requirements for bicycle lighting were set many decades ago, and were based on the level of illumination obtained with a 3 watt dynamo; they were not based on what is needed to adequately illuminate the road, or on what is needed to be seen by motorists. Vehicle headlights are much brighter now than they were when the bicycle lighting standards were set, and bicycles need correspondingly brighter lights to stand out in traffic.
Conclusion
Each type of lighting system has its pros and cons. The safest lighting systems are the high power halogen lights and H.I.D. lights, powered by a rechargeable battery. Dynamo systems are more convenient, because there are no batteries to worry about, but they cannot provide the level of illumination that can be obtained from battery-powered lights. LED front lights are better than no lighting at all, but are not the best choice.