Tag Archives: reflector

About the bicycle radar reflector Kickstarter campaign

This article has been translated into Portuguese. Brazilian flag
This is commentary about a Kickstarter campaign for a radar retroreflector integrated into a bicycle taillight assembly.

An image from the Web site:

Image from Ilumaware Web site

Image from Ilumaware Web site



One nice thing I can say about the product is that it is quite inexpensive, so I’ll say that first. The reason is that this is not a high-tech product. This is a low-tech component of a system whose high-tech component is in cars.

Retroreflectors work by concentrating light (or in the case of a radar reflector, radar signals) back toward the source. The product is a single cube-corner retroreflector. Optical retroreflectors are the insect’s eye version, with multiple smaller reflective elements, so they work at the much shorter wavelengths of visible light. The technology is described on another Web page.

As to the effectiveness of this product, I have no doubt that it improves the visibility of a bicycle to radar — but…

The product’s Web site repeatedly uses the term “OTR technology”, without ever spelling out the meaning of the acronym. I couldn’t find a definition anywhere online, either. This term makes the product appear more high-tech than it is. Indeed, the site claims:

Stealth techniques use radar reflection to make an object less visible and/or “invisible” to radar. We have reverse engineered this technique into a product used by a cyclist to make you more visible to a car. This is a revolutionary application of radar technology.

Reverse engineering is correctly defined as analysis of an undocumented product to develop specifications for a duplicate or similar product. Examples are the Wright brothers’ reverse engineering the flight characteristics of birds to design aircraft, and Linus Torvald’s reverse engineering the proprietary Unix computer operating system to construct the Linux operating system. The Kickstarter campaign uses the words “reverse engineered” inaccurately, so as to mislead people who do not understand it, as if to mean design of a product to have the opposite effect of an existing product. And when that product is a stealth bomber — wow, now the new product must be extremely high-tech! Again, the product is a simple cube-corner radar retroreflector, as has been used in boating for decades. The designers describe design and optimization of their product, but this is plain vanilla engineering, not reverse engineering.

A radar retroreflector which works in all directions is more desirable, (though it still will not always work, even if a car has radar, because the radar beam may not be aimed in its direction, and there may be a line-of-sight obstruction).

Radar alone as a robotic aid to a human driver is possible, but not very practical. Only a small percentage of cars have radar as of yet. A human driver uses visual cues. A fully-robotic car also must, because not every potential obstacle will be as large or reflect radar signals as well as a bicycle — think potholes, cats and dogs, etc.

The product, as shown on the Web site, includes an active taillight, but no optical retroreflector — though installed in the same location on the seatpost which is usual for one — following in the long tradition of new products promoted as a panacea for cyclists’ conspicuity problems while ignoring basic legal and functional requirements. Most states require a retroreflector or taillight, but any taillight can go out without the bicyclist’s being aware of that, and so any bicyclist who rides after dark should have a rear-facing retroreflector, not only a taillight.

The online promotion entirely fails to mention the need for a headlight, or the legal requirement for one. The Web site shows a bicycle with no headlight.

A bicyclist must always use a headlight at night, because an optical forward-facing reflector does not alert pedestrians or drivers who do not have headlights aimed at the bicycle (cars backing out of driveways, at stop signs in side streets, other bicyclists without headlights, etc.) Still, unlike the optical retroreflectors on bicycles, a forward-facing radar retroreflector is likely to be effective, because a car’s radar is likely to scan in more directions and its pulsed output is immune to interference from other sources. But the retroreflector here is only rearward-facing.

The online promotion also makes a number of inaccurate statements.

 Riding with a tail light [sic] is important regardless of the time of day.

While a very bright taillight can help to alert drivers — human or robotic —  during daytime, reducing the probability of a collision somewhat, there is no law requiring a taillight (or rear-facing optical retroreflector) when riding during daytime.

* “In 2015, more than 35,000+ collisions occurred between cars and cyclists in the U.S. Approximately every 3 minutes, world-wide, 6 people die and nearly 285 people are injured in collisions involving cars and bicycles. The majority of these accidents are from behind because drivers didn’t see the rider and it is NOT because they did not have a tail light.”

This is wildly inaccurate. While rural car-overtaking-bike collisions are disproportionately serious and fatal, only approximately 7% of car-bicycle collisions in the USA are car-overtaking-bike collisions. A very large percentage of these occurs to cyclists riding at night without a taillight! In urban areas, most of the serious and fatal collisions involve turning and crossing movements. No rear-facing conspicuity equipment —  optical or radar retroreflector, or taillight, will prevent most of these. Sure, many if not most car-overtaking bike crashes could be avoided, day and night, by use of a radar reflector, if cars have radar connected to a robotic crash avoidance system — but again, as of yet, only a very small percentage of cars is so equipped. Which takes me to my next quote:

* “In 2016 … there are 470 out of 566 unique car models sold in the U.S. equipped with radar (83%).”

This is very seriously overstated. Saying that a model is equipped with radar is not the same as saying that radar is standard. Adaptive cruise control is still often an expensive option. Only some adaptive cruise control systems include automatic crash avoidance. Some systems use laser ranging rather than radar. The fleet of motor vehicles turns over slowly. More even-handed estimates are found in this article in the Detroit News. Quote from that article:

IHS Automotive forecasts 7.2 percent of vehicles produced globally by 2020 will feature adaptive cruise control, up from 2.2 percent in 2014.

More details and a list of vehicles are on Wikipedia.

Why do promotions like this occur? Fundamentally, because regulation of bicycle equipment in the USA at the Federal level, where equipment standards are set, is a Wild West situation, harkening to the interests of the bicycle industry. That is another story, too big to cover here.










About bicycle lighting and onions

A chance meeting can lead to unexpected discoveries.

I met and spoke with Kurt Cibulski following a reading from a new book by its author, a mutual friend. I had arrived at the reading by bicycle; Kurt and I were talking bicycling. Kurt explained that he has a seizure disorder. The bright, rapidly-flashing LED headlights that bicyclists are increasingly using can initiate a seizure for him. “Who’d ‘a’ thunk it.” thought I.

Who? A proper, national standards-setting body, because someone, somewhere, would have brought the issue to its attention. On second thought, it’s obvious. Flashing lights are well-known to trigger seizures.

It’s also a truism that flashing lights draw attention. Many bicyclists ride in urban areas with overhead lighting, and don’t need a steady headlight beam to guide their way. But on the other hand…there’s the seizure problem.

Without careful standards setting, issues like this slip through the cracks. Designs get based on whim, commercial appeal, economies of production and avoidance of liability risk.

In the USA, individual cyclists are held responsible under state laws for using lights at night, but law enforcement is near-nonexistent, and many cyclists don’t use lights. The USA does have a Consumer Product Safety Commission, which, under pressure from the bicycle industry, has set standards — weak standards — only for retroreflectors on bicycles, never for lights. Retroreflectors only work for drivers whose headlights are pointed at them, and do not light up for the pedestrian stepping off the curb, the motorist in the cross street ahead, two bicyclists on a path approaching each other head-on. Bicycle manufacturers can point to Federal regulations and say that they are doing something for nighttime safety, while not being held responsible for these deficiencies.

This situation holds some ironies and unintended consequences beyond the obvious one that cyclists are being injured and killed for want of lights. The lack of standardization in the USA has given lighting manufacturers free rein to innovate, and has led to the availability of some very fine bicycle lighting systems. In the USA, when you see a cyclist with a light, you will probably see that cyclist from a good, long distance, because the light is a very good light.

In Germany, by way of contrast, lights are required on new bicycles. Manufacturer pressure comes to bear in a different way. To keep expense down, most lights only meet the letter of the law and are are less bright, and much less reliable, than the good ones sold in the USA. Bureaucratic inertia has compounded the problem: Germany requires bicycle lights to be powered by a generator. That made sense 40 years ago when battery lights were weak and battery replacement was expensive. Today’s efficient light-emitting diodes and high-capacity rechargeable batteries make battery lights economical and practical.

Generator lights also have improved, thanks to advances in technology and to discerning European cyclists’ demand for better lights that also meet the requirements of their laws — but a good generator lighting system can cost half as much as the bicycle on which it is installed.

A restrictive legal climate leads to this kind of market distortion; contrast this with the wider scope of innovation and slip-through-the-cracks issues in the US market.

I can’t help noticing that kiosk “bike share” (actually rental) bicycles that are becoming popular in American cities all are equipped with LED headlights and taillights, powered by a generator in the front hub. It only makes sense. The rental agencies have a more direct liability exposure than bicycle manufacturers who sell to individuals. But — the lights on the rental bicycles flash, because the generators produce alternating current and the output is not smoothed. Possibly also because flashing lights are popular and nobody though of the seizure-disorder issue.

Where are we heading with all this? I think that we’re approaching a political tipping point where regulations requiring lights on at least some kinds of new bicycles might be possible in the USA: both because of an increase in interest in utility cycling, and because improving technology had made bicycle lights much less expensive, more reliable and more compact. I mean, if little children can have flashing LEDs in the soles of their shoes, just to look cool, it isn’t much of a leap to think that every new utility bicycle could be equipped with lights.

But we also need to be smart, and look forward as technology improves, so regulations don’t box us in with outdated technology and inferior products, as in Germany.

Now, about those onions:

To give Kurt proper credit in this article, I asked his name and came up with another unexpected discovery. He spelled his name, and then volunteered, “Cibulski means ‘onion man’ in Polish. It’s a pan-European word.” Yes! Again, who’d ‘a’ thunk it? German, Zwiebel. Spanish, cibolla. I looked it up, and found variants in languages as diverse as Basque, Czech, Gaelic, Norwegian, Romanian…

I suppose that there’s another parallel, besides the two unexpected discoveries. Bicycle lighting issues, with all the political and technological complications, peel apart in layers like an onion, too.

Thanks, Kurt!