Bicycle Accident Reconstruction and Visibilty

Bicycle Coalitions Push for Vulnerable Road Users Law

2010-02-12T13:58:00.001-05:00

As more people take to the streets on bicycle and on foot, there is a growing support for changes to laws that govern the roads. One of these laws is the "vulnerable road users law" which would increase the penalties for motorists who cause an accident that involves and injures a pedestrian or bicyclist to more than just a ticket. The ultimate goal is to decrease the occurrence of accidents amongst alternative transportation users and increase the awareness of these people on the roads.

According to reports made by sf.streetsblog.org, the San Francisco Bicycle Coalition (SFBC), Los Angeles County Bicycle Coalition and the Silicon Valley Bicycle Coalition are all working to bring forth this bill at the state level. A similar bill was enacted in 2007 in Oregon that enhanced penalties for injuring or killing a vulnerable road user -- including pedestrians, highway workers, persons riding animals, farm tractor operators, skateboarders, roller skaters, those traveling by scooter, or bicyclists -- without requiring a jury trial.

Chair of the Bicycle Transportation Alliance's legislative committee said the results of Oregon's vulnerable road user law have been "disappointing" and that not one motorist had been charged under the statute. Because the law requires the police officer on the scene to indicate on the ticket that a vulnerable road user was injured in the incident, and no officers have made this indication, it seems that the officers themselves are not educated on the law.

Oregon's law stated that anyone convicted of violating this law could be sentenced to a fine up to $12,500, a year of suspended driving privileges, a court appearance, traffic safety courses and 100 to 200 hours of community service. Certain fines and suspensions could be waived by the court with the completion of other penalties, such as traffic school and community service, promoting education of the road.

Educating the public and law enforcers of the law, along with the increased penalties of the law itself, may prove effective in keeping non-motorists on the road safe and avoiding
The California Bicycle Coalition will be deciding on their legislative agenda for the year in coming weeks and will hopefully have support from local organizations so the legal changes can be realized.

Why Your Attorney Needs Experts

2010-02-12T11:44:00.000-05:00

Often when your lawyer takes your case he retains an expert to assist him.There is a lot of confusion in the general public as to why your lawyer needs to spend money on an expert. As litigation becomes more complex and the need to understand it becomes even greater, the Courts have allowed the use of individuals that are able to act as Friends of the Court. This enables the expert to explain issues to the court that are beyond what a "lay" person is able to do. Some one who is a fact witness can only testify to what they observe. The Expert witness can testify to a broad range of issues within his area of expertise. A physician can testify to cause of death. An Professional Engineer can testify to the causes of failures. A Certified Public Accountant can testify to the finances involved in white color crime. The professional life of an expert can be extremely demanding. Depositions can go on for several days and the questioning can be personal and oftentimes very nasty. In order to qualify before the Court at trial the expert often is subjected to questioning as to his qualifications including collateral issues that are often very personal. This questioning usually takes place out of the presence of a jury. Once the expert is qualified he or she is given broad latitude in their testimony. While the qualification process is demanding, the ability to have an issue explained in precise understandable language, helps the Court understand the complexities of the case being tried. If your issue is valid, it helps your Attorney and you as well.

James Green is a Professional Engineer and past President of the National Academy of Forensic Engineers. He has been practicing as a Forensic Engineer for over 35 years. He can be reached at green@bikereconstruct.com

One Hour Record Progression

2009-11-23T21:45:00.000-05:00

http://bikereconstruction.com/Documents/one%20hour.pdf

The Great Schism: The CPSC Bicycle Safety Rules and the Unraveling of American Bicycle

2009-05-25T11:05:00.001-04:00

Here is a very interesting article that I came across. I think you will enjoy it!

A updated/revised version of the Great Schism by Bruce Epperson was recently published in the Transportation Law Journal Volume 37 Number 2 Summer 2010, a new link will be up soon!

Steel Fork Blade Failure

2009-03-09T15:52:00.000-04:00

Steel Fork Blade Failure from The Cozy Beehive (www.cozybeehive.blogspot.com)

The following graphic shows an old steel fork of a bicycle which, during some repair work at a bike shop, lost its right blade due to a failure at the crown of the fork. The pictures are from Rivendell Bicycle's 2009 web reader, in an article titled "Time & Misplaced Crown Point Broke An Old Fork, Too".

The failure, at the crown on the rear side of the fork, is attributed to the "catching" of the rearward flex of the fork from braking. The flex was directed to a point of the crown which became a stress-riser. Over 30 years, a crack formed, crept around the blade under increasing stress of continued riding. The last picture labels the zones of failure and explains how this fatigue worked its way and some tell tale signs of the failure that can be observed by anyone.In the rest of the article not shown here, Rivendell writes :
"And just for the record, we consider this fork to be worn out, not defective. It was a well-ridden 30 year old bike, and just wore out. Things wear out, even good things. Its hard to call this a defect. Still, there was a reason, as you'll see-and keep in mind that this fork lasted five to ten times as long as many carbon forks made today can expect to last."

Using an Expert Witness as a Landmine: Analysis of Pineda v. Ford Motor Company

2009-03-09T15:48:00.000-04:00

Using an Expert Witness as a Landmine: Analysis of Pineda v. Ford Motor Company

By James J. Donohue and Christopher E. Ballod

Few things can be more important to a product-liability case than the expert. If all goes according to plan, the jury will rely on your expert as a trusted professor who explains the complicated concepts the jury must understand. Accordingly, the trial court is entrusted with the duty of assuring that these powerful witnesses meet a reasonable baseline for trustworthiness before they are allowed to speak to the jury. The Third Circuit’s recent decision in Pineda v. Ford Motor Company [1] poses a potentially troubling development for lawyers facing off against expert witnesses. This article reviews the Pineda decision and comments on its implications for the use of expert witnesses at trial.

General Standards for Introducing Expert TestimonyThe onus of determining whether a proposed expert’s testimony is sufficiently relevant and reliable to go to the jury falls on the trial court. [2] As the circumstances of each case can vary dramatically, a trial court’s discretion to allow or to exclude expert testimony is unassailable, absent some abuse of discretion. There are three factors the trial court must weigh, typically in connection with a pretrial Daubert hearing, when deciding whether to allow expert testimony: “(1) the testimony is based upon sufficient facts or data, (2) the testimony is the product of reliable principles and methods, and (3) the witness has applied the principles and methods reliably to the facts of the case.” [3] An appellate court may not reverse the exercise of discretion “unless there is a definite and firm conviction that the court below committed a clear error of judgment” and based its decision on “a clearly erroneous finding of fact, an errant conclusion of law, or an improper application of law to fact.”[4]

Summary of Pineda v. Ford Motor CompanyPineda v. Ford Motor Company was a product-liability case brought in the U.S. District Court for the Eastern District of Pennsylvania. The plaintiff, Jose Pineda, was an auto technician who was repairing a 2002 Ford Explorer’s rear liftgate when the liftgate’s glass shattered, injuring him. Specifically, when the accident happened, Pineda was tightening a nut that connected the liftgate glass to the frame; he testified at deposition that he torqued the nut according to the specifications in the Explorer manual. Pineda sought damages from Ford.

Pineda retained an engineering expert, Craig Clauser, to support his defective-design and failure-to-warn claims. Ford challenged Clauser’s qualifications and reliability as an expert witness, and the district court held a Daubert hearing. At the beginning of the hearing, Pineda withdrew his defective-design claim.

During the hearing, Clauser, a professional engineer, testified that the Explorer manual: (1) did not state that failure to follow installation instructions for the liftgate glass was a safety issue; and (2) contained the proper procedure for replacing the liftgate glass but did not provide instructions dedicated specifically to hinge replacement. He based his opinion on his review of a remedial 2004 Safety Recall Instruction (SRI) that Ford issued two years after the Pineda accident, which contained an adequate safety warning and hinge-replacement instructions. He admitted that he had not performed any testing or inspections of the product. Clauser also conceded that he was not a warnings expert, but he stated that he believed warnings were “a solution to an engineering problem.” [5]

The trial court excluded Clauser’s testimony, determining that he was not qualified as a warnings expert and that his methodology was not reliable. Pursuant to Federal Rule of Evidence 407, the court ruled that the basis for Clauser’s opinion, the 2004 SRI, was remedial-measures evidence and refused to admit it, thereby precluding the need for limiting jury instructions. The court also determined that even if Clauser were allowed to testify that the warnings in the manual were insufficient, Pineda had no expert testimony about what actually caused the liftgate glass to break. Summary judgment was later entered in Ford’s favor, and Pineda appealed to the Third Circuit.

The Third Circuit reversed both the grant of summary judgment and the underlying order excluding Clauser’s expert testimony. Despite acknowledging that the abuse-of-discretion standard applied, the Third Circuit focused on its legal interpretation of the Federal Rules of Evidence, which warrants de novo review. Thus, insofar as the trial court’s decision implicated Federal Rule of Evidence 702, the panel proceeded to give the trial evidence a “fresh look.”

The Third Circuit first examined the ruling that Clauser was not qualified as a warnings expert. On this point, the Pineda opinion sets out at length Clauser’s qualifications as an engineer, concluding that his “formal qualifications are unassailable.” [6] Under Rule 702’s liberal qualification requirement, the panel held that Clauser did not have to be qualified in the “design of automobile rear liftgates or the drafting of service manual instructions.” [7] Clauser’s expertise in the “stresses and other forces that might cause a material such as glass to fail” was enough to satisfy Rule 702. [8] The panel went on to say that Clauser was qualified to opine that the manual should have had an explicit warning that failure to install the glass properly was a safety issue, even though Clauser was not qualified to testify about how the warning should appear. The Third Circuit was persuaded by Clauser’s testimony that a warning can provide a solution to an engineering problem.

The Third Circuit then turned to Clauser’s reliance solely on his general experience and the 2004 SRI. The panel held that the trial court erred by applying Rule 407 to exclude evidence of subsequent remedial measures without also considering Federal Rule of Evidence 703, which allows experts to base their opinions on evidence that would not otherwise be admissible. This issue had not been addressed by either party, and the panel raised the issue itself for the first time during oral argument. Rule 703 states:

The facts or data in the particular case upon which an expert bases an opinion or inference may be those perceived by or made known to the expert at or before the hearing. If of a type reasonably relied upon by experts in the particular field in forming opinions or inferences upon the subject, the facts or data need not be admissible in evidence in order for the opinion or inference to be admitted. Facts or data that are otherwise inadmissible shall not be disclosed to the jury by the proponent of the opinion or inference unless the court determines that their probative value in assisting the jury to evaluate the expert's opinion substantially outweighs their prejudicial effect.

Based on Rule 703, the Third Circuit held that “it is reasonable for an engineer to rely upon a warning and alternative safety instruction subsequently issued by a manufacturer in forming an opinion that an earlier service manual fails to provide adequate instructions and warnings to automobile technicians.” [9] Clauser’s use of the SRI and his general experience with glass was also enough for the Third Circuit to find his methodology reliable under Rule 702 and the Daubert standard.

The panel noted that, under the “presumption against disclosure of otherwise inadmissible evidence” of Rule 703, in order for Pineda to offer Clauser’s opinion testimony at trial, the SRI need not be disclosed to the jury; should Ford cross-examine Clauser on the basis for his opinion, however, the SRI “would become part of the record for the jury to consider.” [10]

In sum, the Pineda court held that the expert could testify even though the sole basis for his opinion was inadmissible remedial-measures evidence. Furthermore, the appellate judges opined that cross-examination of the expert on the basis for his opinion would open the door to the admission of the remedial-measures evidence. In the end, the defense was left with a poor choice: either allow the expert to testify with impunity or cross-examine the expert only to have the jury hear very prejudicial evidence.

Analysis and ImplicationsThe Pineda decision leaves both trial courts and counsel in a difficult situation. The Third Circuit appears ready to circumvent the deferential abuse-of-discretion standard for reviewing a trial court’s decision regarding the admissibility of expert testimony. Further, insofar as Federal Rule of Evidence 702 will always be implicated by a trial court’s ruling on the admissibility of expert testimony, an appellate court could always choose to take a fresh look at the evidence on the ground that the standard for reviewing interpretation of the Federal Rules of Evidence is de novo. Add to this the liberal admissibility policy read into Rule 702, and it will be a rare occasion for a trial court’s preclusion of an expert witness to be upheld.

Specifically regarding products-liability cases, Pineda stands for the proposition that a failure-to-warn theory may be supported by an engineering expert so long as the expert is generally familiar with the subject matter and the defect is the absence of a warning rather than an improperly labeled warning. Although an engineering expert might be disallowed from offering testimony about how a properly worded label should appear, in cases like Pineda, where a subsequent iteration of the warning appears, this preclusion would not be much of a handicap.

The dynamics of Federal Rule of Evidence 703 are also affected by Pineda. Rule 703 was promulgated with the idea that an expert witness will necessarily rely on texts and other treatises that, in most cases, would not themselves be admissible. Introduction of textbooks generally accepted in an expert’s field is unlikely to be prejudicial, as these materials are almost never central to the facts of the case. Yet the Pineda decision expanded Rule 703 by allowing an expert witness to rely on merely a single piece of evidence that was not otherwise admissible and that was specific to the facts of the case. The SRI Clauser relied on implicated policy concerns central to the prohibition against admitting evidence of subsequent remedial measures. The Pineda decision risks allowing the jury to find that the 2002 Explorer manual was defective based solely on Ford’s improvements to the manual contained in the 2004 SRI. Because Clauser’s expert testimony was based exclusively on his general experience and the SRI, the only way to attack his opinion would be to address the SRI before the jury.

If expert opinions are generally admissible under Rule 702, and Rule 703 is interpreted to allow an expert to base his or her opinion on prejudicial evidence specific to the facts of the case, one could predict that expert testimony might be used intentionally as a vehicle for introducing otherwise inadmissible and even highly prejudicial evidence. And the significance of such evidence would be further bolstered by the fact that it is being introduced through one of the most powerful witnesses in the case: the expert. In short, the Pineda precedent will allow experts to be inserted into cases merely as landmines that could potentially explode the opponent’s position. Pineda marks a further rise in the importance not only of expert testimony but also of developing, as early in the case as possible, a strategy for dealing with these witnesses.
James J. Donohue is a partner in the Litigation Department of White and Williams LLP, in Philadelphia, Pennsylvania; Christopher E. Ballod is an associate in the Litigation Department of White and Williams LLP, in Philadelphia, Pennsylvania.

End Notes

Pineda v. Ford Motor Company, 520 F.3d 237 (3d Cir. 2008).
Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 589 (1993).
Fed. R. Evid. 702.
In re TMI Litig., 193 F.3d 613, 666 (3d Cir. 1999).
Pineda, 520 F.3d 237, 244 (3d Cir. 2008).
Id. at 245.
Id. at 244.
Id. at 245.
Id. at 247.

New on Facebook

2009-01-28T10:47:00.000-05:00

Go to www.Facebook.com to join our group "Forensic Engineering for Bike Accident Reconstruction."

New From the Cozy Beehive...

2009-01-22T13:42:00.000-05:00

This is a post from the Cozy Beehive discussing a specific bike crash and a potential carbon fork failure.

Safety Moment : Crashing Into Pine Needles

Lets get no illusions about our sport.It can get dangerous. Losing just a moment's worth of concentration may be enough to unseat you off your saddle smack into danger.Our second safety moment for the year is Liz Hatch's latest injury report on her blog. As it turns out, she was enjoying the breeze on a fast downhill in a fundraiser ride for the Women's Tour of California Criterium when she approached a corner full of pine needles at more speed than was actually safe. She rode right into the guardrail at 45K and landed face first into the area of needles. Thankfully, she made it but the bike was sheared off at the fork on impact.

For the rest of this post go to http://www.cozybeehive.blogspot.com/.

What to look for from a Bike Accident Expert Witness

2009-01-22T13:28:00.000-05:00

When a bicycle accident occurs, the resulting litigation can have serious ramifications for both the Plaintiff and Defendant. Choosing the correct expert for either side is crucial. These are the basic criteria for choosing an expert that should be carefully considered.
· Is the individual a Professional Engineer by examination? This can usually be determined by the initials P.E.” after their name. The Professional Engineering Examination is 16 hours long and the requirements even to sit for the exam are fairly extensive. Some individuals have the initials “P.E.” and were never required to sit for, or pass, the National Examination. The question that should be asked is “have you ever sat for and passed the NCEES examination for registration as a Professional Engineer?” If the individual has the Professional Engineer designation they are required to conduct themselves under the direction of the Board of the State in which they are registered. This provides the Client the knowledge that the PE, will conduct him or herself in a ethical manner and is bound by the Engineering Code of ethics.

· Is the individual an advocate? Often times a simple examination of the persons website will determine if they espouse some “over the top” opinion. There is no place for an advocate in the court system. If someone is constantly exposing “cyclist rights” or, designated bike ways over bike paths, they are not objective in their opinions. Cross examination is not the place for a “hired gun” mentality- if the individual is constantly talking about cases he “won,” then you do not want them involved in your project. If someone qualifies as an “expert” in a court room they are given wide latitude in what they can say under oath. While the court may allow a hired gun mentality during testimony, the verdict will probably be over turned on appeal ,resulting in large expense for the client. The Forensic Engineer’s role is to be a Friend of the Court and assist the Trier of Fact not brag about “winning” cases.

· Publications. Has the individual published in the Engineering Literature and has the article been subject to peer review. There is a lot of literature in the cycling world on various issues. There is very little literature that has made its way into the Professional literature and is relied upon by other Engineers. A simple inspection of the individual’s web site will determine whether the person just writes in the Cycling Publications or actually publishes in Engineering Journals.

· Racing Background Has the individual had an extensive cycling background? Certainly, having a racing background is a definite plus. Equipment and bike handling capabilities are stretched to the maximum during racing. That “hands on” knowledge is essential for reconstructing bike accidents. However, just because someone “rides a lot” or belongs to the League of American Wheelmen does not make then an expert in Engineering areas such as; trajectory calculations or force of impact on the human body.

· Professional Engineering Organizations. Professional Engineering organizations vet their candidates extensively. If the PE is a full member, or Fellow, in the following organizations their qualifications have been subject to peer review:

o American Society of Civil Engineers
o Institute of Traffic Engineers
o National Society of Professional Engineers
o National Academy of Forensic Engineers
o Practice Division of the State of Registration
o American Society of Mechanical Engineers.

I have been reconstructing bicycle accidents for 35 years. Nothing pleases me more on a project than to have a highly qualified Professional Engineer on the other side of the issue. In these instances, the matter usually gets resolved with a minimum of cost and effort for both sides. There is nothing more difficult than having a “nut case” on the other side that will not take the facts of the matter into account, has a personal agenda, is not qualified, and attacks anyone who disagrees with them on a personal level.

Bicycle safety in bicycle to car accidents

2009-01-19T12:23:00.000-05:00

Go to

http://media.fietsersbond.nl/botsvriendelijkeautos/bicycle_safety_in_bicyle_to_car_accidents.pdf

for a report on why there were more people in the Netherlands getting killed on bicycles than as pedestrians.

Carbon Fork Testing

2009-01-14T15:47:00.000-05:00

Carbon Forks: Testing has shown that these forks are a problem. When the forks are stressed beyond the yield point, catastrophic failure occurs. The forks do an unusually good job of improving handling for a modern road bike. They are light and enable the bike to absorb road vibration and hold a line extremely well. But, when stress is placed on the forks, beyond the yield point, by running into the side of a car or curb (or equivalent) the forks completely break leading to collapse. The “chrome moly” forks that were on bikes for several years do not collapse but bend under similar forces. I will be glad to share data that I have available if anyone is interested. There is peer reviewed data on front fork failure in my Engineering Text – go to http://bikereconstruction.com/aboutthebook.aspx.

LED Lights on Bikes

2009-01-14T10:25:00.000-05:00

Preliminary field results indicate that LED lights on bikes, or used by pedestrians, increase the recognition distance to over 2000 feet at night. LED lights appear to be more effective that none LED lights or retro reflectors at night.

Cyclist Trajectory

2009-01-12T16:11:00.000-05:00

Recently on Cozybeehive.blogspot.com I was highlighted with this article.

On Reaching Dizzying Heights In Bicycle-Vehicle Collisions

"If a car traveling at 46.5 kph hits a cyclist, the force of impact would be sufficient to send the cyclist up to the thirteenth floor of a building."

- Traffico, a journal by the Directorate General of Traffic of the Spanish Ministry Of The Interior

I happened to come across this quote on some helmet advocacy website a few days back. I forgot to bookmark the darn site but had copy pasted this statement exactly as it was into a word file on my computer. Anyway, I was struck and bothered by such a bold claim. While it sounds scary, is there any real truth in it? 46.5 kph is around 29mph, which is a low speed for a vehicle. Despite this, the momentum of the vehicle is a hell of a lot considering its high mass with respect to the cyclist. So can the momentum transfer in the above collision really rocket the cyclist up to as high as thirteen floors before crashing to the ground? If such were the case, the cyclist could be in serious condition, even dead.

If you know your college physics, the topics to recall would be Newton's laws, impact and momentum transfer, conservation of energy, collisions and projectile motion. But hold on. Its a tricky challenge. There are many variables to consider : the masses of the three bodies, height of the cyclist, the gradient of the road, point on the vehicle first struck, orientation of the bicyclist before impact, the launch angle, coefficients of restitution and friction, and victim's behavior post impact (wrap, vault, forward projection, somersault etc).

Physicists and engineers across the world have come up with all sorts of equations to study vehicle-pedestrian collisions. They're interested in things such as - how one can devise a good comprehensive mathematical model that will approximate well the speed with which the vehicle first impacted the victim, or what the total throw distance of the victim would be given other data, or would the model ultimately validate real world behavior - questions of that nature. Such models could then be incorporated into manuals and computer tools that could be used by police officers and forensic investigators to catch criminals and help serve justice.

Example of a Post Impact Scheme Adopted By Bogdanovic and Batista, 2004

Anyway, coming back to my first question based on the initial quote : Can a cyclist really be projected that high, where max height h=height of 13 storeys, about 130-150 feet? We may never know exactly, because not a single bit of data is provided by Traffico other than the car's speed at impact which is given to be 46.5kph=29mph. But lets make an effort to find out.

1. LOOKING AT VIDEOS

Forget the theoretical part for a moment. Lets look at a couple of real collision videos involving a two wheeler and a car.

Here's a guy on a bicycle getting hit by a car. The latter was decelerating hard after the driver spotted the rider coming into his view but it was too late to stop an impact. Note how the right corner of the car impacts the cyclist first. The rider then hits the windshield and bounces off it before falling onto the road on the right side.

The victim is pretty lucky. He just gets up and immediately starts yelling his frustrations. I'm so surprised he didn't smash his head onto the ground. But hey, neither did he fly any higher than the car itself. Just a few feet. The car itself could have been doing 15 or 20 mph before impact.

Here's another video. This time, its a vehicle colliding with a motorcyclist who fled a red light only to meet his deadly fate.

If it had been a bicycle in the video, which is much lighter than a motorbike, it would have been thrown off a farther distance. The car was moving much faster than the first video. It could well have been doing 35 or 40mph before coming to an abrupt stop after the collision. The airbags must have surely deployed since the driver appears disoriented. The motorcyclist is shown spinning in the air at a stomach sickening angle before landing onto the hood of the car and bouncing off it straight onto the road, right in front of the stopped vehicle. Its anyone's guess how many bones he could have broken that day.

And finally, here's a simulation of a car-bicyclist collision. It was done by Crash Teams, the largest crash reconstruction company in the world.

All three of these videos don't show the cyclist being propelled to dizzying heights after the collision. At least not thirteen storeys high.

2. FIELD EXPERIMENTS

Jim Green is a triathlete and Professional Engineer with over 20 years of experience in reconstructing bicycle accidents. In the 19th chapter of his book "Bicycle Accident Reconstruction For The Forensic Engineer", a table of vehicle-bicycle collision data is presented to us. The analysis was done on the field by Rusty Haight and Jerry Eubanks who set up an experiment in which different kinds of motor vehicles were used to strike an exemplar bicycle with a dummy cyclist at various speeds.

Here's the field data that shows the linear throw distance of the dummy cyclist after impact.

Determination of the throw distance of a bicycle and cyclist at various impact speeds

I have highlighted some rows of data for cars close to 29mph. For example, a 1979 Honda Accord hitting the dummy cyclist at almost 27 mph in a 60 degree orientation would throw the rider some 58 feet. Although the field experiment did not measure for the maximum height of the cyclist in the air, I highly doubt that the dummy really went as high as thirteen floors for a throw distance of 58 feet. I don't believe that's what the researchers really observed.

3. PROJECTILE MOTION

Coming back to physics, the cyclist on impact would be a projectile because his motion is only governed by gravity. But can we use the equations from projectile motion to find out what his height achieved could be in an ideal case scenario?

Lets use some simple assumptions like : a) the cyclist is a particle of mass 70kg , b) the head-on collision is elastic, c) the bike is immediately separated from under him after impact, d) the cyclist hits the windshield and is launched forward at an angle, e) during the collision between him and the car, there is zero effect on the velocity of the car itself due to its very high mass and that all the car's impact velocity is transferred to him, f) and the car comes to a complete stop just after impact, leaving the cyclist with the forward motion velocity.

Using the equations for a projectile, we can apply a simple applet to solve for height. Note : This is strictly a 2 dimensional scenario which is not the real case. We're completely neglecting the Z dimension.

For head-on elastic collisions, the velocities of the car and cyclist would be :

Assume the car has mass m1=2000kg, and the cyclist has mass m2=70kg.

v(car) = 13m/s (46.5kph, given by Traffico).

So, v(cyclist) = 25.12 m/s.

According to the equation for maximum height in a trajectory, we find that range is shortest and peak height is maximum when the launch angle is exactly 90 degrees with respect to the horizontal. This is because sin(90) = 1.

Since we assumed that the cyclist hits the windshield, lets give him a launch angle of 80 degrees. Solving :

With air resistance factored in, the cyclist would make a 30.82 m max height, or 101 ft. Add the height of the car's impact point to this figure and it still gives us something under 105 feet. This is not what happens in real at this speed. This is an ideal case scenario where we haven't accounted for the losses in the kinetic energy in the collision. Moreover, a cyclist is not likely to be launched like a cannon, following a perfect ballistic curve . At least that's not what real world vidoes or simulation show us. Lets remember that the cyclist also sits on a bike and that fact coupled with how he impacts the car are very likely to influence how far or high he's thrown. Hence, I cannot validate the calculations above. I may believe it if you're talking about a collision on the surface of the moon where the acceleration due to gravity is 1/6th that of the earth. Ha.

CONCLUSIONS

I won't declare the myth as BUSTED just yet because I have used a number of simple equations with attached assumptions. This is NOT the way to an actual crime scene investigation. I'll be interested in seeing further research data from bicycle-vehicle collision studies investigating multiple accident scenarios. But for now, the idea that a cyclist will launch as high as 13 storeys seems like a wonderfully wacky proposition. I support the wearing of helmets for protection but don't support the spreading of false information by agencies in putting together a helmet wearing agenda.

As an end note, I just thought of something in my hindsight. Maybe Traffico is right. What if, in Spain, the 13th floor of a building is considered so unlucky that there is no 13th floor at all in its elevator's options.

What Traffico then must have actually meant through their quote is : You're one unlucky bastard to be hit by a moving car at 46.5kph!

Concluding video presentation : James Green, PE discusses bicycle accident scene investigation from the perspective of a forensics engineer.

John Forester's Background Including His Stay in a Mental Institution and His Failure in Calculus

2008-03-24T16:48:00.000-04:00

Here is some more infrmation on Forester including his stint in the mental institution

My research, much of it involving the C.S. Forester papers at the Humanities Research center at the University of Texas,shows that John Forester came from a somewhat dysfunctional household, much of it the product of his father's obsessive womanizing.

He (John) started as a physics major at UC-Berkeley about 1946. He failed a second-year calculus exam and dropped out of college and worked in a warehouse in Boston for about nine months, then returned to UC-B as an English major, graduating in August, 1951. He went into the Navy in December 1951 and received a medical discharge in August 1952 after being hospitalized for several weeks at the psychiatric unit at Bethesda Naval Medical Center in Washington DC.

He married an Englishwoman, Jean Labada Clough Nicholson in September, 1953. A son, Geoffrey R. Forester, was born on 4 June 1954. He now lives in Muncy, PA. John Forester went to work in a steel fabrication factory about the time of his marriage and studied at night at UC-B for a certificate in industrial engineering. With this certificate, he received his P.E. from the State of California, probably in 1956. California no longer licenses P.E.s in industrial engineering, which is primarily a business methods discipline, but does maintain the licenses of those who received their P.E.s before they were eliminated.

In March or April, 1958 a daughter Pamela was born. She died in April (probably 11) 1962 of natural causes. Forester and his family moved from Berkeley to Fullerton in the LA metro area in late 1958. He worked at North American Aviation, and probably other places, got his master's in industrial engineering from Cal State Long Beach in 1964 and started to teach there part-time in the business school. He claims that he was an assistant professor, but his textbook, which came out in January, 1968, just before he moved back north, lists him as a "lecturer."

C.S. had a major stroke in 1965, and he and his second wife Dorothy moved to Fullerton in late 1965. C.S. died in April, 1966. In his will, he left John and his brother each $5,000. About twenty other individuals received testimonial bequeaths worth a total of $25,000. The bulk of the estate, about $700,000, went to Dorothy. John and his brother did receive all the literary properties. Dorthy soon returned to England and severed relations with the Foresters.

The will appears to have tripped him out. Within a year or two he quit his job, left his wife and family (he says because she discouraged his cycling, fearing it would bring the opprobrium of their upper-class neighbors) and moved back north to Palo Alto, where he became a bicycle racer, randonneur, and sports car enthusiast. He wrote an incredibly viscous biography of his father detailing every moral and personality shortcoming.
He could not get it published then and sat on it to 1987, when be had a brief excerpt published in American Scholar. In 2000 the whole thing was self-published in a 2-volume set limited to 250 sets. This is the last sentence in the 2000 postscript, which closes out the 800-plus pages:

"I can honestly write that I am better known in my field than my father was in his."

He worked at Xerox in 1970-71, but got fired in 1971. He was working at another high-tech firm in 1972. In 1972 he met Dorris L. Taylor, a cyclist and biochemist visiting from Minneapolis. he apparently talked her and her two daughters into moving to California. In late 1972 he became involved in cycle advocacy and in 1973 he quit work for what he says he thought would be two years full-time work in cycle advocacy while Taylor supported him.
He has, apparently, never worked as an employee since. In 1998 he and Taylor split up (she moved to Fort Collins, CO) and he moved to the San Diego suburb of Lemon Grove. He may be in financial straights; the Sunnyvale house he sold in 1998 had an assessed value of $390,000, while the sales price of the Lemon Grove house was only $143,000; it has only two bedrooms, one and a half baths, and 1043 sq. ft. and was built in 1950.

Johnson v Derby Night time visibility, bicycles and John Forestor

2008-01-18T20:41:00.001-05:00

In this accident I represented the Cycling Company, Derby, in a lawsuit brought by an individual who was driving a bike at night dressed in black down a 15 degree slope without a light. The cyclist hit the rear of a jeep that turned in front of him and was severely disfigured after the jeep drove off and the cyclist was again struck by another vehicle. The Plaintiff claimed that the bike company should have forced him to ride with a light on his bike and that the bike company was responsible for the injuries sustained by the Plaintiff.

The plaintiff was represented by one John Forestor a self proclaimed Bicycling Transportation Engineer. The lay jury jury bought Forestor's diatribe of junk science and awarded a Plaintiffs verdict in the action thus blaming the bike company for not forcing the cyclist to use a light at night. Forestor immediately blamed me for the verdict and launched a vicious personal attack against me that still goes on on his web site.

Since that time I have been urged by several Engineers familiar with Forester's personal attacks to respond more forcefully to his diatribes. Since 1993 I have received numerous projects where Forester was retained and immediately the other side of the action retained me.

I have been reluctant to criticize his personal attacks because frankly they have been very good for business for my Engineering firm. So rather than personally respond to his attacks I will open this blog for anyone who has had experience with Mr Forestor and would like to add their experiences to this post.

2008-01-17T20:38:00.001-05:00

Reconstructing Bicycle accidents at night requires a solid knowledge of visibility and conspicuity.

Bicycles are sold with a retroreflector system that enables a cyclist to be seen by the motorist at a distance of over 600 feet on low beams. In the United States, the law states that Bicycles are sold without lights but with the retroreflector system.

Why Bother with Bicycle Wrecks

2008-01-11T18:35:00.000-05:00

For close to 35 years I have spent my Professional Engineering career determining what causes bicycle accidents. Why bother you would ask? The primary reason I have devoted so much of my career to this issue is simple. The Engineering reasons for these type of accidents can then be used to make cycling safer for everyone. When I can determine that some roadway design contributes to an accident I can then get that information out to the Engineering Design community. If I determine that some type of product defect is the reason the accident has occurred than I can get that information to other engineers or industry personel.

Through the years major adjustments have been made from this work. Point of Sale instructions in the bicycle retail industry has been initiated for Independent Bicycle Dealers (IBD). While most "big box" retailers have ignored the industry standards that the IBD's have put in place it is my hope that eventually they will also initiate these necessary standards.

I have been involved in many controversial cases and projects through the years. I hope to use this forum to comment on some of these and would invite readers to add their comments as well. I will begin with my next posting on an analysis of the Johnson Vs Derby Case that was tried in 1993.