Guest Post: Testing to Destruction

It’s one of the most popular posts ever on this site. And I didn’t even write it. 

A review of ultra-bright bike taillights by Mark Goodley continues to draw readers on a daily basis, over two years after it was written.

The survivor of a near fatal collision, Mark has made it his mission in life to keep others from suffering the same fate. And has put his background as a product design engineer and a licensed pro racing mechanic to use to study how bike collisions happen, and how to prevent them.


Common to physicists and engineers is the requirement to test a product and/or design to total destruction. First we test in computer simulations (via FEA, CFD, or Multi-physics) software, Second; by intentionally pushing well beyond the design limits in real world tests, to produce catastrophic failures.

This is how we learn and improve our designs, and develop an understanding between our theoretical software modeling, and it’s correlation to the physical entity/item/product.

How and why this process is highly relevant to understanding and preventing cycling fatalities follows below.

After countless examinations of police reports, interviews, and scouring though all available data, I started a couple plus years ago with a very simple theory.

IF you ride your bike on roads and streets, with (minimum standard/charged) Ultra Bright Lights, you won’t get hit or killed (from behind at least) by a vehicle. (The bio-psycho-physio-logical “whys and how’s” this works is found in separate articles.)

The theory has seemingly held for over 500,000 bicycle-car related accidents, injuries and deaths in the US over a ten year period. Until this past week, I haven’t been able to find a single verified instance (data collection is ongoing) where a cyclist was hit from behind, while flashing Ultra Bright lights. Half a Million Cycling Injuries and Fatalities (without lights) to 0 (ZERO, with lights). 500,000: 000000.

Even if these numbers could be off by one or two accidents, the long term trend is evident, striking, and alarming.

That statistic changed this past week. Two men were killed (reported by in unrelated “hit from behind” accidents in the Los Angeles area while likely/evidently riding with lights. Begging the question; what made these two different from all the others? What broke down? Is the theory disproved?

So let’s look at the preliminary facts in each of these two fatalities that “broke” the theory.

  1. Each man was riding his bike shortly before, and long after midnight, between roughly 12:00AM and 3:00 AM.
  2. Each man was riding on high speed streets (one on a freeway off-ramp, the other in twisting and turning Fairfax) streets with car sidewalk parking), both without bike lanes.
  3. Each man was Hispanic and over 45 years old.
  4. Each man may have had (only) one bicycle light on the rear when they were hit.
  5. One man was very possibly killed by a drunk/drugged driver.

This is what we’ll call/term Testing a Theory to Destruction.”

Look at what was necessary to “Break the Theory.” Do you see anything even remotely resembling your riding? NO, of course not. How many of us actually get on our bikes after midnight to take a ride?

You had to have a large number of beyond “Perfect Storm” scenarios in each case to kill these two men. An old pilot axiom is: It’s not the 1st or 2nd mistake that kills you, but the 5th or 6th will.

IF anything, these two (very sad) fatalities PROVE the point. To get hit or injured by a car while riding with Ultra Bright lights, a lot of things have to go wrong, all at the same time.

In Summary; what have we learned?

  1. Don’t ride late at night at all, especially after midnight when even the best of drivers are going to be tired, never mind when drunk-drugged up drivers are going to congregate… after the bars close.
  2. Don’t ride on very dangerous roads that are going to be a problem, even under the best of circumstances.   I personally have known the Fairfax area for many decades… and would never ride a bike on it; at least not willingly. IF you HAVE absolutely no option but to ride these streets, take extra precautions. Ride at safe(r) times, with EXTRA Ultra Bright Lights, Don’t ride in black/dark colors, and Still ride at least 5 feet away from parked cars (to prevent getting doored, which is equally life threatening).
  3. Take up the WHOLE lane if you MUST, until it is Safe to move back over to the right. There are some areas I still will only ride the sidewalk.
  4. Be attentive at all times; DON’T BE TOO PROUD to PULL OVER and STOP your bike and WAIT for traffic to pass before crossing dangerous, high speed areas. ESPECIALLY FREEWAY/Highway ON-OFF RAMPS.
  5. Ride with multiple rear lights, (3) three is preferable to “paint” a clear 3D picture in space for a(ny) driver’s mind to immediately identify your location, bearing, and speed. The best lights can be clearly seen and easily recognized from over 1/2 a mile away!!! (in broad DAYlight).   Distance is Time, Time is Early Warning, Early Warning is allowing a driver time to plan (rather than milliseconds to react) and hence accident avoidance, and That is Life.
  6. 500,000:000002 are still pretty good odds… Especially when Your life is on the line. Play the numbers.
  7. STAY ALIVE! ride ULTRA BRIGHT… DAY and night…


Stay tuned. We’ll have another post from Mark next week.




  1. You realize that this is another form of blaming the victims for being on the roads they had to travel to get home from work, right? That it creates a curfew for cyclists to “not be on the streets” rather than for impaired drivers to not be on the streets because being impaired is dangerous at any time. That impaired drivers will target bike lights because they can’t interpret the light as being a vehicle in front of them and stare at it until they run into the cyclist. As much as I would like to prevent every bike wreck, until we remove the cause (motor vehicles driven by fallible human beings) we can’t stop the effect.

  2. goldy says:

    It seems like the person who tried to teach you about what is now called big data is unaware of your continued ineptitude in the science.

    Perhaps my greatest aptitude is instantly ascertaining flaws in models and this is easy to confirm because of historical records, so in the past speculators like you published, and before I know about the leak in the dammed argument, here a pair noted as anomalous but also you write even if minorities living where you do not must perish for heeding your advice in droves that is because they are not like you, and your peers, those you rub co2 cylinders off the compression shorts pockets of when short disposables yourself, are what matter, monoxide dense but near ocean air breathers let’s say, are the dinasoars welcome, most, under your tent.

    The trickle allows that. But you are liable for not telling the a whole story, that drivers suffer rage just from driving, and take it out on who begs loudest, white rage on middle age illegal looking being not the only one’s who will die needlessly from having pierced too many brains, caused too much only accident avoiding pain.

    I have escaped out a front door with a strobe, held center as I passed on the right, back before you put down you HID lamps for SSL beads now climaxing in your character showing not just the theories as destroyed.

    So no friend he realizes nothing. He is violent, mongers for war, welcomes casualties, lusts for bloodshed regardless of collateral consequences, it is the speaking not it’s life in the world that motivated him, the as one rapper noted to a group he hates as well “look at me bitch” over and over again, but this musician was responding not to being overlooked but stalked, And our designer wants us to burn anyone behind us punitively, believing how many of us are killed for it matters not, despite his overt contentions, because provoked manslaughter is illegal, and they where low wage Hispanic’s.

    Right. You belong in Chicago- and failed to include the affluence variable in the datasets sniffed.

    Normal people are not so passively aggressive, they will flick there wrist in relatively huge numbers to darken the roads. Glare, FYI, is already illegal.

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