Category Archives: Bicycling

About the bicycle radar reflector Kickstarter campaign

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.

Retroreflectors have been around for a long time, but the the product 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 characterisics 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.

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

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 toare 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.








Boston expert design

Here’s a video of the intersection of Commonwealth Avenue and St. Mary Street, Boston, Massachusetts, USA, an example of the design expertise which earns Boston its place with the League of American Bicyclists as a Bicycle Friendly City.

The video is from 2013. As of 2016, one change has been made: the zigzag in the bike lane has been replaced by a diagonal transition.

The idea that cyclists should turn across in front of multiple lines of motor vehicles to change lane position is not unique to this location. Here’s another example, and it is by no means the only other one:

I have a blog post in connection with that video too.

Montreal sidepath protects?

A classic right-hook collision occurred on August 26, 2015 in Montreal, where the cyclist was riding on a sidepath.

Here’s a news report on the crash.

As I’ve said repeatedly, sidepaths do not prevent crossing and turning collisions.

The sidepath in this crash is in a block folliwng a steep downhill. The cyclist might have been be overtaking the truck which turned right across his path.

I have cycled through the crash location and shot a video of my ride. It is here.

Rue Berri from Cherrier to de Maisonneuve, Montreal from John Allen on Vimeo.

Michael Colville’s Pitch

About the video here by Mikael Colville of

Mikael Colville’s talk in the video is introduced by a video clip of a rather sorry infrastructure situation, with a crowd of bicyclists slowly making their way forward, cramped in a narrow passage to the right of an opaque barrier, while a line of cars turning right must yield to the cyclists after turning past the barrier. To me, this choice of a clip conveys the message “look, we are morally superior, motorist, we’re going to make it hard for you: you have to yield to us.” It doesn’t say anything about making bicycling more convenient, or anything but a nuisance to people who might think of switching from motoring. Or that whoever chose this location had any other sense about infrastructure — certainly none about sight line hazards.

And the music — the Rolling Stones’ Sympathy for the Devil! Now there’s an odd choice!

Similarly, at the end, there is an overhead drone shot of a bridge which has recently been restriped from four to two lanes of motor traffic, to add street level bike lanes next to already existing bikeways behind curbs. The implication is that bicyclists are winning by taking space away from motorists, and that space is to struggle over, not to share. In this case, on a bridge, I’d agree that bike lanes are suitable, but are four needed? What happens where they turn off at the end of the bridge while motor vehicles can go straight? We don’t see. Who knows?

The talk is all about marketing. The core of his message is that guilt-tripping people about environmentalism doesn’t work, and we must use marketing to make bicycling look attractive. Two products which Colville discusses for purposes of comparison, sewing machines and vacuum cleaners, are both highly useful labor-saving devices which quickly became popular for that reason, but he doesn’t mention that. He does praise improvements which made them more compact and useful in the home, but mostly, he praises the decorations on sewing machines which made them more attractive to homemakers.

My mother owned a Singer treadle sewing machine, and indeed it was a beautiful product — to some degree because of the flower stencils but also because of its elegant product design, with a table to hold supplies and attachments, and into which the machine could be folded down to make the table useful when the machine wasn’t in use. Treadle power was perfect for the pre-electrical era, and the wheel on the right end of the machine could start, slow or stop it with precision. Not to speak of my mother’s machine’s being several decades old and still working perfectly.

My mother also owned a 1950-ish Kenmore (Sears brand, made by Electrolux) vacuum cleaner, and it was an esthetic horror, shaped like an airplane fuselage, painted dull gray and very loud. She made much more use of the vacuum cleaner than of the sewing machine.

Colville says that we must market bicycling like these products. He deprecates “the 1%” of people who will wear fancy cycling clothing” — guilt by association with political class struggle, divisive, and also a reference to the categorization which Roger Geller made up, pulling the numbers out of his head, only to be followed up by a home-town study which found that his numbers were exactly right (surprise!).

Colville says that people are conservative and don’t want to stand out. But, tattoos peek out from under his plain white T shirt.

I don’t think that bicycling can be sold by marketing alone. It must be practical and useful like a sewing machine or vacuum cleaner, or people won’t use it for daily transportation. Though some people like to show off with Spandex and carbon fiber bikes, others wear street clothes and ride beater bikes. Some do both. Should instructors even care? We make bicycling more practical for any cyclists by helping them to do it well — and offering informed opinions on what works, or not, in bicycle planning and infrastructure.

Anne Harris revealed

Anne Harris, author of the BICE study

Anne Harris, author of the BICE study

Here’s a photo of Anne Harris, lead author of the BICE study whose conclusions Paul Schimek has demolished.

A reader has asked how the PowerPoint presentation with speaker notes may be viewed. They’re in the linked document — you just have to download it and have the necessary software. One of my comments on this post gives details.

My reaction is: none are so blind as those who will not see — or perhaps, cannot, in this case, Harris, in allowing herself to be represented in this way. She is standing next to an apparently abandoned bicycle in a bike rack — the rear wheel is obviously bent. In the background, in the street, two cyclists are riding through slush and snow in a bike lane, though the adjacent travel lane is completely empty. The photo appeared with an article in a physics journal (peer review, anyone?) describing the study as a “landmark study”. Another review of the study describing how its methodology failed is here.

Duck Boat crashes

We had a duck boat run into a motor scooter from behind on Saturday, May 7, 2016 in Boston, killing one of the riders. It isn’t clear from the news story why this happened, though I expect that the poor forward visibility from the duck boat was a factor. Did the motor scooter operator pull ahead of the duck boat, riding and stopping in its large blind spots? Or did the duck boat operator run into the back of the motor scooter in spite of its being in hiss field of view? As usual with crashes involving two-wheelers — bicycle, motor scooters, motorcycles — and despite there having been many eyewitnesses, the Boston Globe offers no information as to the cause of the crash. Investigation is underway, although if it proceeds as with recent bicycle crashes, detailed results may not be made available for a long time, if at all.

Another duck boat crash occurred in Seattle, 5 killed, 62 injured — but that one was due to failure of an axle, which sent the duck boat into the side of a bus in an oncoming lane of traffic.

What is to be learned from these crashes?

For one thing, the duck boats are surplus from the Second World War. Though they served gallantly in that war, they are over 70 years old now: mechanical failures are not out of the question. The duck boats’ design as amphibious vehicles placed the driver high above the road over a high hood, with poor visibility to the front — a problem which has led to fatalities of pedestrians in crosswalks with large trucks. The duck boats do not have a front bumper, but instead, have a hull which can push unfortunate pedestrians, cyclists and vehicles underneath. These vehicles probably would not be legal, except that they are antiques.

Another issue with the Boston crash may be of education. Did the motor scooter driver not understand the peril of riding in blindspots of large vehicles? Boston is relentlessly installing bicycle facilities which direct bicyclists to ride into blindspots. It does not appear that the collision involved any such installation, but motor scooter operators are permitted under the law to use them, and their existence, along with a lack of instruction as to their perils, contributes to hazardous behavior elsewhere as well.

In the context of all these issues, my misgivings about the Vision Zero campaign described in the Boston Globe on April 17 need no further mention.

Rear-view radar reviewed

Garmin is a high-end manufacturer of GPS devices for bicycles and motor vehicles.

Garmin has posted an ad for a cycling “radar” (probably actually LEDdar using pulsed infrared light), which warns cyclists of overtaking traffic. There are some serious problems with the product concept and with the ad, so once you’ve viewed the ad, please read on.

The $200 Garmin device, an accessory for a bicycle GPS unit which costs several hundreds of dollars, informs the cyclist that a vehicle is about to overtake. But in order to decide what to do about that, the cyclist needs to know how much clearance the vehicle will give. The Garmin device doesn’t provide that information.

The stilted British voice in the ad conveys an air of authority, I suppose, but how is the cyclist in the ad not going to HEAR the huge truck approaching from behind? Unless the cyclist is listening to something at top volume on headphones — but I didn’t see any. The cyclist never once is shown looking back, and he isn’t using a mirror, and so what is the device supposed to let him know that he wouldn’t know anyway? Granted, the device could give a warning of a quiet car.

The “cyclist’s eye view” clip in the video shows his response to the warning: pulling over to the right edge of the roadway, so far that grass would be brushing his right foot and he risks a fall on the cracked pavement — which could turn a brush-by into a fatal.

Imagine what a nuisance this device would be when being passed by strings of vehicles. It would give a continuous warning, which would provide no useful information. One more good reason to use my $15 rear-view mirror to check on overtaking traffic, and use my cell phone for GPS (no extra cost) and forget Garmin!

The ad repeats the figure from a League of American Bicyclist survey of fatal bicycle crashes, that 40% are in overtaking crashes. That widely publicized number has several problems though:

  • First of all,  there are more problems with the numbers. My friend Patricia Kovacs comments:

    LAB’s Every Bicyclist Counts study found 40% of bike fatalities were hit from behind. I’ve been studying crash data in Ohio and in 2015, 30% of bike fatalities were hit from behind. But not all hit from behind are the motorist’s fault. In Ohio, 15 out of 24 fatal bike crashes were the fault of the cyclist, 6 were the fault of the motorist and 3 were no error, according to the police officers’ reports. What were the circumstances for the cyclists at fault? Improper crossing, not visible, failure to yield, lying or illegally in roadway. Most of these circumstances can be mitigated with education. I do worry about drunk and distracted drivers though, which is why I use a mirror.

  • The LAB study is biased in covering only fatal collisions, which are rare. Just as an example, in the over 100 million miles of travel in the 50-year history of the bicycle club to which I belong, approximately 1000 lifetimes of riding for an avid cyclist, there have been only two fatalities to club members. One was a rear-ender and the other was a head-on collision with an out-of-control vehicle that crossed to the wrong side of the road. Non-fatal crashes are hundreds of times as common and result in far more loss of years of useful life. 3/4 of serious bicycle crashes don’t involve a motor vehicle at all.
  • The League puts forward the 40% figure to promote its support for barrier-separated bikeways in urban areas, but fatal overtaking crashes occur mostly on rural roads. Most urban fatalities result from crossing and turning movements.

Half-truths have been used repeatedly to sell cycling infrastructure (as with the League’s study) but Garmin’s is the most sophisticated use of half-truths I’ve seen so far to sell a cycling product, while also being seriously ill-informed.

The Slow Ride, redux

Bob Sutterfield writes:

I don’t ride fast so I can participate safely in traffic. I participate in traffic so I can safely ride fast enough for my needs.

If I were to ride in the gutter, on the bike path, in the door zone, on sidewalks and cycle tracks, etc. I could reduce my risk (probably to an acceptable level) by traveling slowly – at near-pedestrian speeds. That slower speed would give me more time to react to the hazards present in those environments.

But I use my bike for purposeful travel. I don’t have time in my day to travel as far as I need to go, if I were constrained to moving only at near-pedestrian speeds. In order to get where I’m going in a practical amount of time, I need to be able to ride at the speeds I’m capable of sustaining on a bicycle. And I need to do it more safely than if I were in the gutter or on a bike path or in the door zone – I need the safety and convenience of the travel lane. That speed is what the travel lane is designed to accommodate, and that’s what the ordinary traffic laws are designed to enable.

If my choice of travel by bicycle is restricted to hazardous areas like gutters and bike paths and cycle tracks, I’ll choose another way to travel – something motorized so I don’t suffer those restrictions.

Misleading poster redux

seattle poster

Seattle poster

The panel at the right is from a poster called The Commuter Toolkit put out by International Sustainable Solutions for an organization called the International Sustainability Institute. You may view it full size by clicking it or view the full poster. This poster shows a scene in downtown, Seattle, Washington, USA and the poster bears the names of various sponsors in the Seattle area.

The comparisons of space used by different travel modes in the poster are misleading. They show the space which people occupy standing still in posed photos, not the space which each mode of transportation actually uses. Cars would not be spaced so closely if in motion, and they also take space to park. Nor would buses be spaced so closely, and they also use bus stops and bus garages. The bicyclists are standing over their bicycles, not riding, etc. Neither does the poster address the throughput and travel times for the different modes or the suitability of different modes for different trips of different distances. I addressed an earlier example of a similar poster on this blog but there’s a twist to this particular version: the bicyclists are shown riding down the middle of Second Avenue in Seattle, but look over to the right side of the picture: that’s a bike lane — also with cars in it in the car picture. Similarly for the bus-only lane at the left side of the photos. No train runs on this street!

The bike lane was more recently replaced by a two-way separated bikeway, into which speed humps are being installed because the bikeway cannot safely support normal downhill bicycle travel speeds on this sloping street, though that’s another story.

The location, in case anyone wants to take a closer look.

Lane Control on Lexington Street

Here’s a video showing a bicycle ride on a constant mile-long upslope, at speeds of 10 to 12 miles per hour (16 to 20 km/h), on a suburban 4-lane speedway with narrow lanes and no shoulders, the most challenging street in the community where I live. Motor taffic was very light, and auite fast. Points made:

  • Lane control is not about riding fast: it is about controlling one’s space.
  • Lane control is necessary so motorists will overtake at a safe lateral distance on a street with a narrow right-hand lane.
  • By requiring motorists to make full lane change, lane control lets a cyclist with a rear-view mirror confirm well in advance that motorists will overtake with a safe lateral distance.
  • With the light traffic on a multi-lane street, a slow bicyclist does not cause any significant delay to motorists.
  • Most motorists are cooperative.
  • A few motorists are abusive — even though they can easily overtake in the next lane —  but they too overtake safely.
  • American traffic law supports lane control.

Lane Control on Lexington Street from John Allen on Vimeo.