Bicycle Light FAQ
Question: What does “German test mark” mean?
Answer: Lighting on vehicles such as cars or bicycles is subject to legal regulations. In Germany, the StVZO regulates the nature of “lighting equipment on bicycles”. This specifies which requirements a front or rear light must meet. The Federal Motor Transport Authority checks whether a manufacturer meets these requirements. If a bicycle light meets the requirements, this model receives a so-called “K number” or test mark. The test mark confirms that the lighting complies with the StVZO.
Question: Can I also use lights on my bike that do not have a test mark?
Answer: As soon as I move in road traffic in Germany, I must ensure that my lighting is StVZO-compliant. The rules in the Road Traffic Regulations are designed to protect all road users. Lighting that does not conform to the StVZO can dazzle other road users and thus endanger them. The only exceptions are personal safety lights that are worn on the body or on clothing and serve as supplementary lighting.
Question: What is lux?
Answer: The unit lux measures the illuminance on a surface and is made up of the luminous flux (lumen), and a certain area. An illuminance of 10 lux is equivalent to 10 lumens per square metre. For bicycle lighting, the lux number is measured only in the centre of the light cone.
Question: What does lumen mean?
Answer: The unit lumen indicates the strength of the luminous flux and measures the luminous intensity emitted by a light source at a certain solid angle. Thus lumen says something about the radiant power of a light source.