Bicycle lighting
A secondary purpose is to illuminate reflective materials such as cat's eyes and traffic signs.
The earliest bicycle lamps were oil-fueled and started to be manufactured in 1876 for the Ordinary (High-Bicycle) and solid-tired tricycles.
The light given was very bright, often called artificial daylight but the lamps required regular maintenance.
The lights used by most halogen rechargeable systems were cheap and bright, but fairly simple: they projected a cone of light (wide and narrow beam options were available) which is good for off-road use but not ideal for road use as it can dazzle oncoming road users.
Many systems used standard commercial prefocused optics, making a wide range of power and beam width combinations available.
High-intensity discharge (HID) lights were a brighter/more efficient alternative to filament bulbs prior to the widespread adoption of LEDs.
[citation needed] Like halogen systems, they were designed primarily for off-road use, having rotationally symmetrical beams which cast as much light up as down.
HID lamps were susceptible to damage from repeated strikes, and in many cases did not relight immediately after shutting down.
But the longer battery life than halogens tends to negate these problems, as many riders would simply switch the light on and leave it running throughout the ride.
Xenon strobes were an innovation in bicycle lighting; previously common in industrial applications.
The main advantage with this voltage is versatility of the electric system, such as the ability to charge a cell phone battery, though 5 volt USB is also used for that purpose too.
Article 44 of the Convention stipulates that: "Cycles without an engine in international traffic shall: (c) Be equipped with a red reflecting device at the rear and with devices such that the cycle can show a white or selective-yellow light to the front and a red light to the rear."
In some countries, for example France, it may be an offence even to sell a bicycle not fitted with legally compliant lighting system.
CPSC compliant reflectors (also commonly fitted in other markets) have three retro-reflective panels positioned at 30° angles.
The use of lights for night riding is generally recommended or required by authorities as a basic safety precaution, even in a well-lit urban context.[6][7][8][9][which?]
White LEDs are available with output ranging from a few lumens to high-powered units producing about as much light as an automotive headlamp, suitable for high speed use on unlit trails.
The round light pattern of a general purpose flashlight is inferior to the beam of a bicycle headlamp properly shaped to illuminate the roadway and not provide excess glare to oncoming traffic.
[14] Many vendors claim EU compliance, however, this provides no consistent safety or legal value across the Union.
These battery packs usually strap to the top tube of the frame, or come in the shape that fits in a water bottle cage, or can be placed in a basket.
More specifically, the 18650 battery, which has been popular with electric car manufacturers (for the same reasons) and are commonly found in laptops and flashlights.
The most common design includes a magnet on the wheel spoke and lights with a coil in them, mounted on the frame or fork of the bike.
Reflectors and reflective tape provide additional visibility (especially when applied to moving parts of the bicycle) and are mandatory in many jurisdictions.
The law is rarely if ever enforced, but could potentially be used in court to reduce financial compensation if the cyclist were to be hit by another vehicle.
A single solid colour can disappear under artificial light, particularly yellow sodium vapour lighting, and colour blindness is common; red/green colourblindness can make yellow fluorescent vanish against a green background (hedges or grass), although people with red/green colourblindness dispute this.
Vests with both yellow and orange fluorescent areas plus wide strips of reflective may be the best solution.
In recent times electroluminescent clothing has become available to add to the existing array of LED-illuminated armbands and helmet blinkies.
Due to persistence of vision, individual lights mounted on the moving bike’s wheel spokes are perceived as glowing arcs or circles.
The glowing rims or wheels can isolate the bike from the visual noise of the city lights and help drivers see and immediately recognize a cyclist.
Despite its complexity, it is a more useful measure than watts, because it defines how much usable light is shed in a given place: a dynamo headlight designed for road use and focused for seeing the road makes more efficient use of the power of the lamp than lights using rotationally symmetrical optics.
