The CPSC's Plan for
Nighttime Bicycle Safety Research

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Meeting of 13 March 1996

1 The Meeting

The Consumer Product Safety Commission of the United States called a meeting of those interested in the requirements of the CPSC's standard for bicycles that pertain to nighttime safety of cyclists. The meeting was held on 13 March, 1996, at the CPSC's headquarters in Bethesda, MD, close to Washington, DC. More than 30 people attended, representing reflector manufacturers (9), the CPSC itself (7), cyclists (5), bicycle manufacturers (4), news (2), highway management (2), nighttime research (1), highway safety (1), and others.

2 The CPSC's Plan

Regardless of what those invited might have thought beforehand, the main purpose of the meeting turned out to be the presentation of the CPSC's research plan and solicitation of the audience's suggestions thereto. Because the presentation and the plan were both thoroughly inept, there was much confusion until the audience discovered what was intended. The CPSC said that their data showed that nighttime cycling had a risk 7.5 times that of daytime cycling. (Don't place too much credibility in this. Those of us who have studied the CPSC's data know that the risk factors are very inaccurate.) The CPSC initially confused accidents with fatal accidents, giving the wrong numbers. They stated that the objective of their research was to evaluate the adequacy of the present reflector requirements, investigate possible improvements, and report recommendations for changes in the standard.

I won't take the space to copy the proposed methodology: you'll just have to take my word for the ineptness. The CPSC planned to use 40 motorists, one at a time, driving at night in a residential area. The motorists would be instructed to talk about what they saw and to push a button on the steering wheel whenever they saw something "that may appear to be in the roadway ahead or that they believe may eventually ender the roadway (i.e., cross their path)." The motorists would be instructed to push the button a second time "when they believe that they have identified the object," meaning that they think that they know what type of object it is. The observer riding with them will say "yes" if the identification is correct, and "no" until it becomes correct. Among the objects to be seen and identified, six will be cyclists. The bicycles will be equipped with the following types of equipment: (1) the currently specified reflectors; (2) head and tail lights; (3) helmet with reflective markings; (4) amber instead of red rear reflector; (5) & (6) to be determined from discussions with the industry.

It appeared that the CPSC personnel did not know much about the operation of retroreflectors. Early on I asked them if they knew what the observation angle was and what it signified, and received no reply. Fortunately, towards the end of the meeting Ken Uding, a cyclist who is also an executive with a former reflector manufacturer, presented a good lecture with first-rate images on how retroreflectors work and are measured and what the measurements mean.

It turned out that the bicycles were to be motorized. The audience wasted much time discussing methods for trying to correlate the movement of the bicycles with the motor vehicles when on intersecting paths. That is, until it also turned out that the motorization was merely to turn the pedals and wheels while the bicycles stood on stands, to avoid the danger of having a human cyclist hit by an errant motorist.

I repeatedly told the CPSC that unless they had good data on the types of accident that were caused by darkness they could not determine how to conduct the test. They replied that they had good data, that is that they hoped to work up good data from the information that they possessed. Having seen other examples of their data, I was not impressed, and told them the method that had to be followed to get good accident data, the way that Ken Cross had done in his studies. It became obvious that they had no plan and no money to get data sufficiently accurate and relevant to do the job, yet they were not really considering the use of the Cross data either.

However, these inadequacies and concerns turned out to be irrelevant because, as we found out after much discussion, the CPSC was going to test only one position of cyclist and motorist, when a motorist approaches a cyclist from behind. If that is all that they are going to test for, then the test results apply to only that type of accident and, technically, it doesn't matter whether that is a frequent or an infrequent type, and the test results will not apply at all to any other type, no matter how frequent or infrequent.

3 Other Discussion

Richard Blomberg, who had done a similar study some years ago, provided several items of information. He used an army reserve base that is uninhabited during the week, necessary to control the tests. Humans respond best to the image of other humans, so mannikins should be on the bicycles. He thinks that the sight of a single reflector or lamp, particularly if red, is likely to be disregarded by the mind as being too distant to be significant. The human response is likely to differ from the photometric response. He wants to see some kind of rear equipment that provides a distance clue. However, when this was discussed, it was thought that a pair of reflectors or lamps could not be as far apart as on a car but that the viewer would judge distance as if they were that distance apart, thus greatly overestimating the distance to the cyclist.

Regarding the choice of red vs amber, Blomberg thinks amber is best because it is brighter and because red is seen as more distant than it really is, while Uding thinks that red is psychologically more stimulating than amber, a factor that does much to overcome the lower brightness of red.

Blomberg said that the CPSC would not be doing research, merely evaluation. Therefore, the CPSC should decide which systems of equipment would be politically acceptable and test these to determine an order of efficacy, so that the best could be recommended for adoption into the regulation.

Blomberg also remarked that he is doing a restudy of the Cross data, a project that was delayed "because there wasn't a bicycle safety problem during the Reagan years."

Cyclists all said that lights are absolutely necessary. James M. Green, who testified in the Johnson vs Derby case that the front reflector was an entirely adequate substitute for the headlamp, now stated that anyone who rides without a headlamp is an idiot.

Noel Weyrich, director of state and local advocacy of the League of American Bicyclists, asked whether motorists who hit cyclists from behind had misjudged the clearance distance. They need to give cyclists 5 feet of clearance even if they give stationary objects only 2 feet. He remarked that alcoholics who are prohibited from driving motor vehicles now ride bicycles, and said that we need publicity for the use of lamps. Don Tighe, director of communications for LAB, asked whether the CPSC had a program for telling motorists to give adequate clearance when overtaking cyclists.

Michael Kearshaw, the representative of the Bicycle Manufacturers' Association, argued against testing a bicycle that was equipped with headlamp and taillamp, obviously concerned that these would show how bad the all-reflector system was. He said that it was obvious that lights were better than reflectors, so that what we needed was a program to educate users about that, and that our focus needed to be on the users rather than on the product.

4 Formal Presentations

4.1 Cateye

Cateye made the first formal presentation. They showed how improvements in reflector technology had allowed reflectors to become smaller while still meeting the specified requirements. They also showed some rear lights in which the lamp shone through a CPSC-specified rear reflector.

4.2 3 M Company

The 3 M Company put on its usual big show of products that they want to sell. They gave to the CPSC several studies presumably published in refereed journals about the ability of people to recognize objects equipped with two reflective circles as bicycles or motorcycles. Their current version of the reflective tire sidewalls idea is reflective rings mounted to the spokes just inside the rim of the wheel, and they went all out trying to demonstrate the virtues of this system. Of course, in the process they showed, to those of us who know, that they were making outrageously incorrect assumptions about the mechanisms of car-bike collisions. However, I do not think that the CPSC people understood the extent to which they were being duped.

3 M Company also showed their new design of reflector. It is very flat, looks like sheeting, and it can be applied over a layer of fluorescent paint, so that the item exhibits fluorescent colors in daylight and retroreflects over a wide angle at night (maybe 75 degrees from the center line).

4.3 Reflexite Company

The Reflexite showed a bicycle that had many parts of it, particularly the sides and the inner wheel rims, coated with reflective sheeting, presumably similar to the 3M product. Because the material is transparent, it does not discolor the bicycle during daylight but is retroreflective at night.

4.4 Others

Two other individuals showed different types of wheel reflectors. One was made of the 3 M sheeting, triangular in shape to fit the triangle between spokes about 3 spokes apart. The other was also made from the 3 M sheeting, mounted on flexible mylar, and designed to fit between the wheel reflector and the rim, extending sideways out from the wheel so that it could be seen from behind.

4.5 Ken Uding

Ken Uding, a cyclist and an executive of a company that used to make reflectors, presented a lecture describing how retroreflectors operated, were measured, and the significance of the various measurements. This was certainly what the CPSC people needed. He emphasized that reflectors must not be specified for brightness at only one distance, but for the three distances that are significant in accident avoidance. He remarked that in daylight fluorescent colors are only a little brighter than the surrounding background, but that at night reflectors are many times brighter than their background. Therefore, reflectors are much more useful at night than fluorescent colors are in daylight. He also said that headlamps are absolutely necessary and that we need an official program to so inform people.

4.6 Forester

I recommended a policy for the CPSC. We know that headlamps and rear reflectors are required when riding at night, both for safety and by the states. The CPSC's legal authority extends only to time of sale; that is a constitutional limitation that we cannot alter. It is absurd to require headlamps at time of sale because most bicycles will never be used at night, and because even if a bicycle will sometimes be used at night a lamp bought at time of sale is quite likely to be inoperable after being exposed to the weather for several years without being used.

However, we also know (statistics presented) that the present all-reflector system has persuaded the majority of the population that it is safe to ride at night with only that system, without headlamps. We need a system that does not mislead people and gets them to use headllamps and rear reflectors at night.

Since, at the time of sale, the CPSC cannot distinguish, either legally or logically, those bicycles that will be used at night from those that will not be used at night, the CPSC ought to limit its consideration to the only reflector that is in a position to actually prevent accidents, the rear reflector. If the CPSC requires only that reflector, then no state or other division can require any other reflectors at time of sale, which satisfies the bicycle manufacturers' old concern when they had to ship different kits of reflectors depending on where the bicycle would be sold. Without the misleading reflectors, fewer people will ride at night without headlamps and those that do will have no reason to sue the bicycle manufacturer for misleading them.

When they heard my proposal to do away with the majority of their compulsory reflector sales, the reflector manufacturers raised objections. They argued that the wheel reflectors disclose the presence of children playing in the street. I replied that if the wheel reflectors shone in a motorist's headlamps, either it was too late to avoid a collision or, if a collision did not occur, the cyclist had left the motorist's path before the motorist had reached the cyclist and the cyclist would have to turn completely about to get into the motorist's path again. Then they argued that wheel reflectors simply show that child cyclists are in the area.

Somebody asked me for the basis by which I said that when the cyclist and the motorist would collide at an intersection, the wheel reflectors would not be illuminated in time to avoid the collision. I replied that motion and time analysis of the movements showed that this was so. The 3M representatives replied that with fast cars and slow cyclists this is not so. So far as the image is concerned, the wheel reflectors will show, but cars travel fast only when they have the right of way, as on streets protected by stop signs, so the motorists assume that the cyclist will stop at the stop sign. If the cyclist does not stop, then a collision will occur, just as it would in daylight.

5 Technical Considerations

The CPSC is likely to propose some new reflector requirements as the result of this activity and the study that it will perform. However, I am unable to make any reasonable prediction about what form those new requirements will take. There is no evidence that the CPSC will study and will act in a reasonably competent manner. Regardless of the inability to predict what might be proposed, cyclists need to consider their strategy, to be ready when the CPSC does act.

5.1 Limitations of the CPSC study

The CPSC's proposed study covers only the situation in which the motorist overtakes the cyclist. This is the only situation for which reflectors have been tested by someone clearly independent of a reflector manufacturer. The CPSC's study determines only two things: the maximum distance at which the bicycle is seen and the maximum distance at which the bicycle is recognized as a bicycle. The results of any test should be evaluated directly on the ability to avoid a collision, rather than on some other characteristic, such as recognition of the type of object to be avoided.

The fact that the only tests that are unprejudiced by reflector manufacturers cover only the approach from the rear says clearly that there is no scientific justification for reflectors that face in any other direction. Considering the evidence that reflectors facing in other directions do not shine at the time that the collision can be avoided, the limited testing ought to limit the CPSC's authority to issue requirements for other reflectors. Reasonably, it would. Whether the CPSC will act in accordance with the limits of its tests is another matter.

5.2 Types of Car-Bike Collision, the Duty to Yield, and Observing

In considering the need to see another vehicle in order to avoid a collision, there is a great difference between the situation in which the observing driver must yield to the other, and that in which the observing driver has the right of way. The rules of the road are structured so that when a driver has the duty to yield he has the opportunity, in daylight, to see the other driver so that he can yield. In this case the ability to see the other driver is mandatory. When considering nighttime collision situations, it is mandatory that whatever equipment is provided for nighttime conspicuity work for all the situations in which the observing driver must yield.

It is different for the situations in which the observing driver has the right of way. He does not have to see the other driver at all. If the other driver makes a mistake and does not yield, only then does it make a difference if the driver with the right of way sees him, and in most of these cases there isn't sufficient time and distance to avoid the collision.

Therefore, bicycle nighttime equipment must be visible for all the collision situations in which the bicyclist has the right of way, but it is not nearly as important for those situations in which the bicyclist must yield.

5.3 Seeing, Recognizing, and Observing

There is an argument that the mind sees only what it considers significant and discards the rest. The argument has two different parts that must be distinguished. The discarding can be either instantaneous or later, by failing to put the image of the sight into long-term memory. The failure to remember afterwards whether one saw an object along a journey does not indicate that one did not see that object and consider it important at the time. At the close of most trips practically none of us can tell the type and color of the vehicles we interacted with at First and Main, even though, on that trip, we changed our course or speed to cooperate with their drivers as we passed through that intersection. No test or question that depends on long-term memory can be an accurate measurement of usual, non-remarkable, things or events.

The only situation in which the mental characteristic of discarding an image applies to nighttime car-bike collisions is if the motorist optically saw the cyclist but instanteously mentally discarded the image because it seemed unimportant. The argument is made that if motorists see a pattern of lights that clearly indicates that it comes from a bicycle, they will less often discard the image and will therefore more often take the appropriate action to avoid a collision. This is the argument used for wheel reflectors and pedal reflectors.

There has never been any experimental evidence for the hypothesis. To test the scientific theory would require that the test objects be equally optically visible, but one would present a significant pattern while the other would not. I do not know whether or not that has been done. To test this particular engineering application would require that the test objects be the best practical items for the application. For example, test clear pedal reflectors against a headlamp, for frontal conspicuity, and against a bright, efficient rear reflector for rearward conspicuity. No studies sufficient to demonstrate the engineering hypothesis have been published. The one study that I know of, my own, is merely a brightness comparison of clear pedal reflectors against the 3" diameter amber SAE reflector, as observed from an approaching car. That test showed that the SAE reflector was visible at a greater distance, and always appeared brighter, than the pedal reflector.

Then how strong is the argument? Consider at first the rural nighttime scene. Every lighted object on or near the road is significant. The motorist's mind is not going to think that any lighted object does not matter. Everything that is lit, whether it has one light, or two, or a lighted bar, or whatever, is something that must be avoided. There is no other choice. The argument is very weak for rural nighttime scenes. Much the same conditions apply on surban residential streets, and therefore for nighttime car-bike collisions on them.

Consider the urban scene with distracting lights. In those situations in which the bicycle's lights are among distracting lights from other traffic, the presence of the other traffic indicates the danger to be avoided. A cyclist's headlamp may not be observed when seen among the headlamps of other motor vehicles, but then the observer has to take the same action with respect to those motor vehicles as he would for the bicycle. The same goes for the rear light or rear reflector of the bicycle when seen among the tail lamps of motor vehicles. Under some conditions, a cyclist's headlamp may be presented against a background of roadside lamps. In this case the oberver is looking diagonally across the roadway to observe the approach of the cyclist. However, for the cyclist's headlamp to be against such a background, the cyclist must be quite close already, so that the motion of his headlamp very obviously distinguishes it from the background.

Therefore, I see very little force in the argument that a bicycle with merely one light visible is likely to have its image discarded by the mind of any observer who needs to see the bicycle at night.

5.4 Side Reflectors and Recognition

5.4.1 Side Reflectors Generally

The argument for side reflectors is that the bouncing motion (conventional wheel reflectors) or ring shape (the 3M proposed rings) disclose the presence of children playing on bicycles in the roadway in the dark. Even if the cyclist that is observed moves out of the motorist's headlamp beams, so the argument was given at the meeting, the motorist ought to slow down and yield, just in case the same cyclist, or any other one, swerves across the motorist's path.

In answer, I think that this scenario has been far-fetched by the reflector manufacturers. I have seen no data showing that young children playing in the roadway on bicycles in the dark is a significant cause of casualties. We do know that the age distribution for nighttime car-bike collisions is considerably higher than the age distribution for daytime car-bike collisions, largely because children stay home during darkness. The CPSC should not require all cyclists to carry wheel reflectors just because a very few of the youngest commit a particular type of mistake. Even if the CPSC requires wheel reflectors because they cost so little, the CPSC should then require the bicycle manufacturers to state explicitly the purpose that they serve, so that those cyclists who don't play in the roadway can discard the wheel reflectors without detriment.

5.4.2 The Wheel Reflector Rings Proposed by 3M Company

The 3M Company presented several published papers purporting to show the great advantages of the 3M reflective ring wheel reflectors. Having heard the spiel of the 3M representative when describing these papers, I have the greatest doubts about their relevance to preventing nighttime car-bike collisions. I will need to obtain copies of these papers before saying more about them.

5.5 Pedal Reflectors and Recognition

Two arguments are made for pedal reflectors: they are more likely to be seen than the other rear reflector and they indicate a bicycle. As for being more likely to be seen, nobody has published the proper test of comparing a clear pedal reflector against an amber 3" diameter SAE rear reflector. On the basis of area and color absorption, the amber rear reflector is more than 5 times brighter than the clear pedal reflector. My own tests show the difference. Therefore, it is not very likely that the pedal reflector will be seen and the other will not be seen.

As for the indication of a bicycle, one asks what should the motorist do differently for a bicycle than for a motorcycle, or for a car with one tail lamp, or for a tree with a reflector on it. In each case, the motorist will steer to miss the lighted object, whatever it is. The only argument for pedal reflectors is that the cyclist might be more likely to swerve across the motorist's path than the other objects. If the assumption is that the cyclist will swerve, then how much additional clearance should the motorist allow? To what extent should requirements for bicycles be applied to all bicycles to compensate for unlawful actions by some users? The words of the representative of the League of American Bicyclists emphasizing that nowadays alcoholics ride bicycles at night homeward from their bars indicates the faulty reasoning that all must be treated as the worst, that all must be equipped as if they were drunk merely because some do drive when drunk.

5.6 Child Cyclists and Alcoholic Cyclists at Night

The arguments for more equipment than the headlamp, rear reflector, and optional rear light are all based on the idea that cyclists performing foolishly unlawful acts need to be seen and identified by motorists while in the unusual positions that they might assume on or approaching the roadway as a result of their behavior. As we know, the ability to see the cyclist in more different positions is not a very effective way to prevent car- bike collisions, because most of those cyclists whose reflectors are seen are not those that are in danger, while it is very possible for cyclists whose reflectors are not yet seen to ride into a collision. A headlamp would serve all of these cyclists better than any number of additional reflectors.

The principal types of cyclists who are alleged to operate in this manner are young children and alcoholics. The data show that children incur proportionally fewer car-bike collisions at night than do adults, entirely because parents do not allow young children to cycle at night. As for alcoholics, it is not fair to require additional equipment on every bicycle just because some of them will be used by drunks, and, besides, it is even more important to keep away from drunks the excuse that the additional reflectors make it safe to ride without a headlamp.

In addition, as we have already seen, requiring the additional reflectors has persuaded very large numbers of normally rational and law-abiding people to perform the foolishly unlawful act of cycling at night without a headlamp. In short, requiring the additional equipment has persuaded far more people to cycle dangerously than the likely number of people whose other foolish actions would be mitigated, to some extent, by additional reflectors.

5.7 Type of Rear Reflector

Amber is brighter than red. Since the only direction that a motorist approaches from the rear is from nearly directly behind, the SAE type of reflector, with 20 degrees on each side of the center line, is better than the wide angle type, which sacrifices 2/3 of its brightness to provide reflection from directions from which motorists do not approach.

5.8 Reflector Manufacturers

The reflector manufacturers want to sell their products by having them specifically required by a government regulation. The trouble is that almost nothing that they have to sell (the rear reflector is the exception) has any real use in preventing casualties to cyclists. 3M Company has traditionally put on the most intense displays of products. No information about bicycle reflectors that I have seen in the past from 3M Company has been scientifically accurate so far as preventing cyclist casualties is concerned. The company has always promoted some form of reflective wheel with the propaganda that recognition prevents collisions, when such recognition is neither necessary nor is it possible, not through reflective wheels, at the time that collisions can be prevented or for the purpose of preventing collisions. The Reflexite approach is different in form, outlining the frame rather than the wheels, but it is still recognition through side view under conditions when side view of reflectors is impossible at the time when collisions can be prevented.

Those people who are seeking financial rewards by selling equipment that is supposedly for safety purposes should have their products scrutinized very carefully with respect to the function that they actually perform, including making profits, and the opinion of those who will actually buy those products, and use them if they find them useful, should be considered very seriously. If the well-informed users consider the products largely useless for the intended safety purpose, and specifically less useful than other products, then such products should not be specified.

6 Conclusions

We do not know what will be done next. However, there is no evidence now, and the CPSC's planned study cannot provide any, that the front and side reflectors now specified in the regulation actually reduce accidents to cyclists. We know that a headlamp is required, we know that the CPSC cannot reasonably require one at time of sale, and we know that the states require one when cycling at night. Therefore, we should be ready, again, when the CPSC next takes action, to make the point to the CPSC and to the bicycle industry that the only reasonable requirement for the CPSC is the rear reflector in amber SAE form.

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