Getting evidence in slip and fall accidents and building failures with video taken from a drone

I’m using drone-mounted cameras to get video of sites where people slip and fall and buildings fail.  The evidence is different, easy to get and cost effective – a few hundred dollars depending on location.  See Examples below also the References.

I take video almost exclusively because the resolution is so great in frame grabs that stills are not necessary.  Video is normally shot at 30 frames per second.  You can fly as fast or slow as you like, dip up and down, slip sideways and hover – videoing all the time.  Altitude and speed are recorded, and GPS on some drones.

There’s nothing technical about this.  You can get video with a simple, inexpensive camera fixed to a drone flying a few feet, 10s of feet or 100s of feet above and all around the site of an accident or failure.  The first aerial video I had taken was with a GoPro camera like those attached to a skier’s helmet for a scary run down a mountain.

Video from aloft is not the only means by which evidence is collected during a forensic engineering investigation.  This way, however, is relatively new, simple, cost effective and the evidence is from a different angle and sometimes quite revealing.  A DVD of the video on everyone’s laptop also enhances conference calls.

Following are some ways I’ve used video taken from a drone in recent years, or might have, and ways I may do in the future:

Example #1 Recently.What better way to survey and record defects in a high retaining wall involved in a flooding problem than from a few 10s of feet above the ground and off the face of the wall?  Example #2 Or identifying the potential location of fuel oil spilled on different properties as evident from distressed vegetation and colour changes in the ground so visible in a video taken from a few 10s of feet high?.

Example #3 A choice application would have been capturing the re-enactment of a nail gun accident on video from a few feet and right over the scene.  Unfortunately, there was no room for a drone to hover in the tiny room that was available – the actual scene was more expensive.

Example #4 My forensic investigation and re-enactment a few years ago of the John Morris Rankin accident at a test site at the Shearwater Airport would have been a perfect application of aerial video as would filming the 75 foot cliff over which John drove in Cape Breton.  As it was, I got good aerial video of the test site from a Sea King helicopter borrowed for the purpose.  I also got footage from the top of a rented boom truck.  Today I would use a drone fitted with a video camera.

Example #5 Quite recently I thought to use a drone to get video at a step-down and stumble accident site where there was lots of room to hover.

Example #6 Even more recently I’ve thought of using a drone to video the re-enactment of slip, trip and fall accidents in public places where I know there is lots of room to hover.  Places like auditoriums, sport’s facilities and airport terminals. 

You can grab frames at 1/30 second intervals from a video of a re-enactment and study slight changes in the movement of the slip and fall victim.

Techniques like these are being used now to estimate the speed of cars and airplanes in accidents.  Resolution is so good that you would be able to see the nail in a nail gun accident from 200 feet up – if there was an airport terminal with a ceiling that high.

There is also some chance that study of the condition of the floors as seen in the videos  - subtle changes in pattern, colour, texture, material or workmanship that contribute to floor skid resistance, – would cast light on the cause of the accidents.

This is like terrain analysis in civil engineering, – a well developed method – except indoors rather than outside.  The terrain’is a floor rather than the ground down hill of a fuel oil spill or along the proposed alignment of a highway.

Example #7  Also extremely valuable - surveying damage to the side of a multi-story building with a drone-mounted video camera – the former provincial land surveyor in me is enthused about this one.

Video could be taken from a distance of a few 10s of feet to document the character and extent of the damage to the wall, then from a few 10s of inches to measure the damage.  No expensive scaffolding necessary and workers climbing up and down.

Scale for measuring what is seen in the video would be got from the known size of building components used to construct the wall.  For example, the known size of a concrete block and the known thickness of the grout between concrete blocks

The character and configuration of the wall damage, and the size of cracks often points to the cause of the damage.  Random hairline cracks due to normal material shrinkage?  No worries.  Cracks that exhibit a predictable configuration and need to be grouted tell quite another story.  The cause is often almost a given, and would be one of the ways buildings fail.

Studies of how buildings fail have identified at least 209 different ways and they’ve all got causes. (Ref. 3)  And these don’t include all those involving the foundations and foundation soils – too often the Achilles’ heel of designers and builders.

***

This method – taking aerial video with drone-mounted cameras – is being used now in North America.   (It’s a new application of photogrammetry – the identification and measuring of the size of things on the earth as seen in photographs taken from the air)

Using video shot from a drone has got to be one of the most cost effective forensic engineering methods to develop in a long time.  Getting a lot of evidence quickly and cheaply is not too hard to take.

Like I said above, the savings continue when you distribute a DVD of the video to the parties involved for a conference call while each party views the scene on their laptop or device of choice.  I did this during one forensic investigation and surprisingly got more evidence still from comments made during our discussion.

With today’s technology, you can even ‘crew’ on a drone flight as ‘navigator’ by standing next to the ‘pilot’ flying the drone and direct the video to shoot from a remote display.  The video takes on more meaning when you’re part of the action.  I also end all my videos with footage of the pilot and myself, sometimes the plaintiff, standing on the site so there’s no question we were there.

References

  1. A picture’s worth a 1000 words, possibly many 1000s in forensic engineering with a new aerial photographic technique. Posted January 15, 2014 (see aerial photographs from a drone flight in this blog)
  2. New forensic aerial photographic method proving extremely valuable. Posted January 30, 2014
  3. How many ways can a building fail, and possibly result in civil litigation or an insurance claim? Posted July 10, 2014
  4. Forensic photography – the expertise available in eastern Canada. Posted February 26, 2015
  5. Fixed wing drones – another tool in forensic engineering investigation. Posted November 4, 2015
  6. “Crewing” on a forensic drone flight. Posted October 4, 2016
  7. Getting evidence with a low cost, low tech drone flight over a forensic site. Posted March 31, 2017
  8. Conference call on a “drone flight” reduces cost of civil litigation. Posted May 18, 2017
  9. “Unexpected” evidence and the importance of drone photography in forensic investigation. Posted July 19, 2017
  10. Drone video as a forensic technique is joined by drone photography as an art form. Posted August 2, 2017

Update: How I was tyrannized by the obvious during an engineering investigation

Who would have known that condensation was the real cause of the flooding in a furnace room – or so it seems now.  But don’t hold your breath at the rate this saga is unfolding.  Also note that forensic investigations can go off the rails like this too.

I blogged earlier (see below) on how I investigated the cause of flood water on a furnace room floor in a vet clinic and how I concluded it was obviously due to a high water table beneath the building.  Also how I was told later that it was really due to a burst water pipe in the washroom adjacent the furnace room after staff went there and saw water on the washroom floor.

The story could have ended there with me learning a valuable lesson, that if it seems obvious keep on investigating.  But it didn’t; my lesson continued a few days later.

Vet clinic staff called a plumber about the ‘burst pipe’, he came and investigated, saw the water on the washroom floor, looked for a burst pipe but found none.  He then looked in the washroom on the floor above.  Still no burst pipe but he did find water on the surface of the cold water pipes in the washroom.  The water was dripping on the floor and in turn on the washroom floor below next to the furnace room.

Water vapor in the moist washroom air had condensed on the cold water pipes.  This would be the same as vapor condensing on the inside of a window in the winter and water running down the window.  We’ve all seen that I’m sure.

So, the flood water in the furnace room was caused by condensation on cold water pipes, not by a burst pipe and not by a high water table.

To take inspiration from a quote by Hunter S. Thompson, “Wow! What a lesson!”. (Ref. 1)  I’ll keep you posted in the event there are more chapters in the saga.

You might ask, what’s this got to do with forensic engineering investigation?  It’s a reminder, that if being thorough in the investigation of water on a floor in a small room in an old building is important, it’s light years more important for the simplest of forensic investigations.

Reference

  1. Thompson, Hunter S., “Life is not a journey to the grave with the intention to arrive safely in a pretty and well preserved body: but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming “Wow! What a ride!”. (As cited recently at the celebration of a friend’s life)

***

Earlier Blog: How I was tyrannized by the obvious during an engineering investigation

It can happen to any of us, and it finally did to me.  I was tyrannized by the obvious when investigating the cause of flooding in a large, three story building.

A building renovator called me after water was seen on the furnace room floor by staff of a veterinary practice.  They had gone to the room where materials were stored and saw a few millimetres of water on the floor.  Not a lot but still.

The renovator said the building, which was erected in the 1960s, was on a concrete, ground-floor slab, on low land and near a lake.  The furnace room was enclosed by concrete block walls.  The flood water had pooled on the slab.  He estimated that the concrete floor slab was about five feet above the nearby lake surface.

When i went to examine the site I saw that the five feet was about right and that the furnace room was an estimated 50 feet from the lake shore.  I was also told that the lake level was higher than normal due to a lot of rain this spring.

The grounds around the building sloped down slightly to the lake shore.  The front and right side of the building were paved.  There was a lawn at the back and an old paved boat ramp on the left.  The surface of the boat ramp was bumpy after many years.

The corners of the furnace room were still wet where the concrete block walls rested on the concrete floor.

I had a good look around then walked across the floors of the different rooms in the practice.  They were a little uneven which wasn’t so unusual for an old building.  But my look around wasn’t as good as it might have been and I neglected to look in the small room adjacent the furnace room.

My examination complete I met with the owner and the renovator.  I noted how the water rises in a lake during frequent rain storms.  It also rises in dug wells.  The water in a well is the water table. The surface of the water table in the ground near a lake shore is usually higher than the lake.  There is also water in the soil above the water table due to capillary action – this is when water rises in the small voids in the soil above the water table (Check high school physics)

This higher water table plus some surface water runoff across the asphalt at the side of the building could explain the presence of the water in the furnace room.  It was obvious.  I mean, the building was so close to the lake with high water levels not seen in recent years and the furnace room floor was near the lake surface and the water table.

The irregular boat ramp was typical of frost heave due to water in the ground – a high water table and capillary action during wet springs over the years – and would back up this obvious conclusion further.

I talked about different ways of preventing water getting into the furnace room.  These included the obvious – terrible word – better perimeter footing drains and/or a sump pump.in the furnace room.  A sump pump is a pump in a depression or hole in the ground – a sump.

The sump pump was decided on as the least expensive and one that could be constructed several feet below the water table to draw it down below the furnace floor.  That decision was left with the building renovator.

I left the site after about an hour – an efficient examination and consultation, or a  hurried one?

A few hours later the renovator called to explain that a staff member had gone in the wash room – the one room I hadn’t gone in – adjacent the furnace room and found a burst water pipe, the real cause of the flood in the furnace room.

I was tyrannized by the obvious and guilty of expectation bias.  The moral of the story?  If it’s obvious, keep on truckin’ and do more investigation.

So, who knew the St. John River would flood like that?

I thought of the news reports on a Friday or Saturday that predicted the Saint John River flood would peak the following Tuesday.  And that happened as predicted.  But I was surprised that the record-breaking nature of the flooding was not also predicted – a week, 10 days or two weeks beforehand.  I can’t help but think that somebody knew or should have.

I’m certain there are well-developed and accurate models of flow in the St. John River and of contributing factors in the river’s watershed including snow cover and weather.  These would be hydrologic and meteorologic models developed from empirical data collected in the watershed over many generations if not centuries.  We have models in forensic engineering investigation that serve us well too.

Sounds technical but hydrology is simply the study of the flow of water in a watershed and meteorology is the study of weather.  Put them together and you’ve got a powerful tool for predicting if a river is going to flood, when this will happen and how high.

A model is simply a set of ideas and numbers that describe the past, present or future of something such as an economy, business or, flow in a river.  Models are built using measurements and observations – empirical data – of the things that characterize what you’re interested in.

A street map is a model.  It shows the location of streets and other features of interest in an area.  Things like businesses, buildings, the local coffee shop, etc.  It doesn’t show things you’re not interested in like the height of the buildings and the level of the streets.

Good and accurate models:

  • Fit the empirical data from which they’re built
  • Explain past observations – like why the river flooded in the past
  • Predict future observations – like when the river will flood again
  • Are simple and inexpensive to use

Exhaustive data collection and study of flow in the River would have been done for design and construction of the Mactaquac Dam in 1968 – a few kilometres up river of Fredericton – and during the 50 years, half a century, after the Dam was operating.  So why not an accurate prediction of the historic flooding – not an inch or so above all previous highs but something like a foot?

We rely on models in the forensic engineering investigation of the cause of foundation failure.  Foundation design and construction is closely tied to the semi-empirical science of soil mechanics – a science partly based on measurements and observations and partly on theory.  This science developed in the early 1900s and holds us in good stead in a forensic investigation.

Annual flooding in the St. John River was being recorded each year long before the early 1900s, and the weather – temperature and rainfall – and conditions in the watershed – snow pack – were being noted.

So, I would put my money on the existence of accurate models that would predict with a respectable degree of accuracy, a week or two in advance, that New Brunswick was going to be flooded-out.  These models would include data on how the Mactaquac Dam is operated in storing and releasing water.

I was in contact with a professional forester who lives in Douglas a short distance up river of Fredericton.  He wonders too about the flooding and also noted the Dam and it’s operation as a feature in the watershed.

I can’t help but wonder if a similar situation exists in British Columbia with the flooding there.

References

  1. Giere, Ronald N, Bickle,John, and Mauldin, Robert F., Understanding Scientific Reasoning, 5th ed., 2006, Thompson Nelson, Toronto
  2. Wikipedia, May 14 and 15, 2018

How you can help break the expert evidence logjam

It sounds like a commercial but you can help break the logjam by reading Dr. Ruth M. Corbin’s paper on how we experts are helping. (Ref. 1)  Then you suggest what might be included in follow-up studies to her pilot study of 152 experts.

You might remember from my blog earlier this week that the logjam is the different perspective of expert evidence held by the courts as distinct from the experts. (Ref. 2)

Ruth calls for follow-up research on the following questions:

  1. Empirical research to strengthen the evidence-based foundation of future policy
  2. Economical modeling to complement the Supreme Court’s call for a “cost-benefit” analysis of expert testimony, and,
  3. Practical steps toward creating a forum for direct communication between experts and courts

We’ve got to get Atlantic Canada input to these follow-up studies – there’s no information on the role we had in the earlier studies.

In my earlier blog, I suggested including the following in follow-up studies: :

  1. Future studies and perspectives must be evidence-based.  I was prompted to suggest this on learning that the court’s view of expert evidence as revealed in the pilot studies was not so evidence-based.  It was this view as I understood it that influenced the policy on rules governing experts
  2. Economic modelling to complement the Supreme Court’s call for a “cost-benefit” analysis of expert testimony must include an identification of the principles governing the cost control of civil litigation involving experts.  You can’t do a reliable cost-benefit analysis without accurate expert costs arising from conformance to these principles.
  3. The role of the middle man, the advocate, in direct communications between experts and courts must be carefully spelled out.

Summary

Read Dr. Corbin’s paper – you’re in for a treat -, and possibly my blog and take on the situation, then send your comments to her.  Don’t be too refined, just get something out there like in brain storming.  Send your comments and suggestions to info@corbinpartners.com  I found Dr. Corbin’s assistant very good, responding quite quickly to my queries and promptly forwarding comment onto Ruth.

References

  1. Corbin, Ruth M., Chair, Corbin Partners Inc. and Adjunct Professor, Osgoode Hall School, Toronto, Breaking the Expert Evidence Logjam: Experts Weigh In, presented at Expert Witness Forum East, Toronto, February, 2018 (Google the paper and Ruth’s name)
  2. How experts are helping break the expert evidence logjam.  Posted April 30, 2018

Guidance for Canadian experts – with a little help from the USA?

You might be interested in the 2nd annual Expert Witness Forum in Toronto later this month.  The two day conference is being held at the Marriott Bloor Yorkville on February 28nd and March 1st.

The speakers cover the standard topics of interest to experts in half and three quarter hour talks for a total of about 11 contact hours in the two days.  There’s also a panel discussion, a round table, a case study and a keynote speaker on the agenda.  And lots of networking sessions and refreshments:

  • Expert report writing
  • Peer reviewing reports
  • Mistakes experts make
  • What lawyers look for in experts
  • Preparing experts for cross-examination
  • Principles governing communicating with experts
  • How technology is impacting expert witness testimony
  • A judicial assessment and a legal practitioner’s views of expert witness testimony
  • Using expert evidence in arbitration

The speakers come from the judiciary, law firms, ADR firms and firms providing related services to the judiciary process.

There’s no indication of take-aways and handouts but I would look for something on these important topics as they reflect Canadian practice.

I’m pleased to see such a forum in Canada emphasizing the way it is here.  SEAK Inc. and Expert Communication Inc. in the USA have been holding conferences and workshops for the guidance of experts for decades.  Much of their extensive literature is applicable in Canada.

I have about five of SEAK’s texts covering the listed topics above including the massive, 560 page, 8″ x 11″ second edition, 2014, How to Write an Expert Witness Report.

Hopefully, the conference in Toronto later this month will also reference what has been going on in the USA and bridge to a wealth of information there for Canadian expert witnesses.

You can see the complete agenda and register at the following site:

https://www.canadianinstitute.com/expert-witness-forum/

How do you get hard evidence from soft data?

How do you get evidence about the speed of a car from cracks in the pavement or trees at the corner?  How do you get reliable, quantitative evidence from the qualitative data on a mobile phone?  Evidence that will stand up in court?

This is being done now by a new forensic investigation method.  It requires knowing what to look for in the phone’s video, some measurements with a carpenter’s tape, Google earth, a little junior high math and lots of software.

It’s called video velocity analysis, a scary title but remember: Carpenter’s tapes, junior high math and modern technology make it happen.

Video of aircraft accidents taken by witnesses has been analysed since 2008.  The crash of TransAsia flight 235 on February 4, 2015 in the Keelung River shortly after takeoff from the Taipei Songshan Airport was caught on three separate witness cameras, and was subsequently analysed.  Video of traffic accidents is now being done the same way.

Reliable forensic evidence

The qualitative data on traffic cameras and car dashboard cameras is also being used, as well as mobile phones to learn the speed of a car at the time of an accident.  In fact, it was the cross checking of an assessment of car speed from three different sources of soft data - mobile phone, traffic camera and dash camera - in field trials with a car with a speedometer and GPS, that has demonstrated the accuracy of this new method.

How accurate is an assessment of car speed using these types of simple cameras?  Depending on the circumstances, within about 2 km/hour – pretty hard evidence in a court case.

Google Earth sometimes figures in this type of assessment as well.  How accurate is the quantitative data from the eye in the sky, kilometres high?  How about within a few centimetres on the ground in urban areas.

Evidence based on junior high math 

The basic principle is simple enough.  Measure the distance between two points on the ground seen in mobile phone video, note the time on the video for the car to travel this distance, divide one by the other – junior high math – and you’ve got your car speed.  Photogrammetry, the science of making reliable measurements using photographs, is sometimes used in this work but the principle is simple.

What does the analyst look for in the mobile phone video, traffic camera or dash camera?  Basically, anything on or near the ground that can give distance that can be correlated with time which is also taken off the camera.  Things like the distance between construction cracks in the pavement, dashes on road centre lines and lane markings. The analyst is also interested in anything that can be seen on Google Earth.

Car speed in accidents has been measured other ways for years and continues to be.  Using mobile phones is new, can be more accurate and provides an opportunity for the cross checking essential to good engineering and applied science.  I had the cross checking of data drilled into me by Major James A. H. Church when I studied land surveying at the College of Geographic Sciences. (Ref. 1)

Explained in Moncton, NB in 2017

This all came out in a lecture I took last fall in Moncton by Major Adam R. Cybanski, Gyro Flight and Safety Analysis, Ottawa, on a new technique for learning car speed in an accident. (Ref. 2)

Major Cybanski has been instrumental in developing the technique using the simple, inexpensive mobile cameras that are everywhere today.  He specializes in video analysis and accident reconstruction for aircraft and auto accidents.  Adam flew all manner of aircraft in the air force over the years, slowly moved into the investigation of the cause of aircraft accidents and more recently into auto accidents.

And used in court cases

He believes he is one of a few in the world using this analytical technique.  In 2016 he had one case, but this grew to 14 cases from different accident sites in the world in 2017.  Video speed analysis has been used in several court cases and as of March, 2017 has not been contested.

An analysis took him many months initially when he was developing the technique using witness video.  It is something he can now do in a few days, depending on the location of the accident and the features visible in the video.  Time is spent cross checking an analysis; getting the car’s speed from more than one camera.

Vehicle speed is just one element in accident reconstruction but an important one.  Adam gets camera data sent to him from the principle investigator wherever he or she is in the world, analyses the data and sends the auto speed back to the investigator.  He doesn’t need to visit the site in most cases.  His speeds have been validated using speed radar guns, GPS and Event Data Recorders – the “black boxs” installed in some cars to get information during accidents.

The lecture was organized by CATAIR, the Canadian Association of Technical Accident Investigators & Reconstructionists, Atlantic region.  Dr. Stuart Smith, secretary of CATAIR knew of Major Cybanski and his technique and suggested inviting him to Moncton to speak.  Stu reconstructs traffic accidents in his practice including analysing vehicle speed. (Ref. 3)

The take-away

What’s the take-away from this blog?  A new and accurate method is available to check vehicle speed in an accident as determined in more conventional ways.  The results are reliable and accepted as evidence in court.  And expertise is as near as your e-mail.  The speed of anything that moves can be analysed if caught on a mobile camera.

References

  1. Church, Major James A. H., founder and first principle of the Nova Scotia Land Survey Institute, 1947, forerunner of the College of Geographic Sciences, Lawrencetown, Nova Scotia
  2. Cybanski, Major Adam R., Gyro Flight and Safety Analysis, Ottawa, 2017 http://www.gyrosafety.com  (Adam and I conferred about this method as it’s new to me too)
  3. Smith, Dr. Stuart, C. R. Tyner and Associates, Dartmouth, Nova Scotia   crtynerassociate@eastlink.ca

 

 

 

An expert for every civil litigation lawyer in SEAK’s Expert Witness Directory 2018

This Directory contains over 1,600 expert witnesses indexed by over 23,000 categories – or different areas of expertise!  Most are located in the U.S. but some are in Canada.  I thought to give you a sampling of the categories but picking something representative seems impossible.  You can check them out at www.seakexperts.com

The experts are listed alphabetically by state, province and name.  Their names are given, location, telephone number, often enough a website. area(s) of expertise, number of times deposed/testified in the last 4 years, education/qualifications and years in practice.

SEAK, Inc. is a U.S. based expert witness training company in business for at least 30 years.  Their literature indicates they have trained thousands of expert witnesses through seminars, conferences, on-site corporate training, and by working one-on-one with individual experts.  The training is hands-on and covers areas such as report writing, depositions, direct examinations, cross examinations and ethics.

I attended one of their conferences and a workshop another year.  They are good and well organized.  I also have several of their books including both on expert report writing which are excellent.

It’s interesting, that while a number of their books are on testifying and cross examination, they list training in report writing first.  As adversarial as the U.S. seems, the great majority of disputes are settled out of court, and I’m sure this due in no small measure to good expert report writing..

You might take a look at their website.  While most of the civil litigation in the Atlantic provinces doesn’t need highly specialized experts from away, it’s nice to know the resource is there.  I could have used an expert in the design and manufacture of a power tool recently – and the expertise is listed in the SEAK directory – but my preliminary work saw the direction the investigation was going and that was enough.

Drone video as a forensic technique is joined by drone photography as an art form

I enjoyed learning recently about the annual international drone photography contest.  The contest was mentioned in the papers and, of course, I learned more by Googling.  I liked what I read and saw.

The contest recognizes that drone photography is more than fun indulged in by hobbyists with $300 drones and more than a surveillance technique used by the RCMP with $30,000 gear.  It’s an art form, and on the list with its use as a valuable forensic engineering technique using a $10,000 drone fitted with a camera.

The winning and runner-up photographs in the contest are impressive - you must go online and see if there is an artistic bent to your nature at all.  Impressed is the way I felt too when I first saw drone video of one of my forensic sites.

The contest photographs are submitted in four categories: Nature, People, Urban and Creativity by drone photographers from everywhere in the world.  Profiles of the professional and amateur photographers are included on the contest site.

The photographs are judged by a panel of experts that include representatives from National Geographic in France and the US, and from Kodak.  Both companies are two of several high profile sponsors of the annual competition.  This year, 2017, is the fourth year the contest has been held.

Such quality in photography and high profile in contest sponsorship is telling about the future of this photographic technique.  It echoes the increasing success I’m having in my forensic investigations getting evidence with a drone and presenting it to my earthbound clients.

Credits

  1. Some of the content in this blog has been taken from the drone contest website and also a conversation with Robert G. Guertin, Millenium Film & Video Productions, Dartmouth, NS, Canada.

 

Using “Skippy”, a full sized dummy, to get the speed of a car in a fatal traffic accident

How fast was he driving when he hit the girl on the sidewalk?  He’s dead now after falling asleep at the wheel, hitting the girl then hitting a pole.  So’s the girl after sliding several metres in the grass.  Speed is important in reconstructing an accident like this.

His speed can be assessed from the damage to his car.  It’s called a “crush” analysis, not surprisingly.  The assessment can be cross-checked with a different analysis using data from the skid marks of the girl in the grass.

Experts in accident investigation like to cross-check assessments like these – and also refine the analytical methods with new data.  Some of the methods are rough and seemingly not very scientific but that’s hands-on engineering and better than nothing.  If you can measure something – e.g., skid marks, crush shape - even approximately, you can “manage” it; in this case get the speed of the car.

That’s what I was doing last week at a meeting in Moncton of CATAIR, taking part with about eight others collecting data for the continued refinement of an analytical technique.  This time using the skid marks of a body in the grass for determining the speed of a vehicle during an accident.  It sounds complicated but a lot of it boils down to determining the coefficient of friction of a surface like in simple high school physics.

With enough testing, chaps like Mike Reade, Moncton hope results will benefit investigators in situations when they only know the pedestrian’s sliding/tumbling distance after an accident.  The results will be shared with others who work in this field. (Refs 1, 2)

In this case, Mike, who was directing the research and will crunch the data later, threw Skippy, a full size dummy, from a speeding pickup truck driven by Ken Zwicker, Bridgewater.  The rest of us carried out various tasks like spotting where Skippy hit the ground, measuring how far he slid and videotaping what happened to him after he was “hit” by the truck.  Katelynn Everett, a consulting professional engineer from Fredericton, recorded data and did preliminary number crunching.

The field trials are part of the very impressive, ongoing work by CATAIR, the Canadian Association of Technical Accident Investigators and Reconstructionists, and others to refine the analytical methods used by traffic accident investigators. (Refs 2 to 7)

The association is a mix of serving and former RCMP and municipal police officers, professional engineers and technologists all of whom are interested in traffic accident investigation and reconstruction.

In the morning before starting the field trials we met and discussed about 12 different courses on topics related to traffic accident investigation that are available to CATAIR members.

CATAIR meets somewhere in the Atlantic provinces about three or four times a year and do field tests most times.  Recently three teams measured the crushed shape of three different cars that had been involved in traffic accidents.  Each team is analysing speed using different methods and comparing results – Stu Smith, Dartmouth gave a brief report at the meeting on his work on this.  Another time the stopping distance of a vehicle on a road was measured.  And another time still, the turning radius and the path of the rear wheels of a school bus were measured.

Nobody gets paid for this field research.  It’s all to do with refining our understanding of the cause of traffic accidents and reconstructing these, and the camaraderie of like-minded people working together – we do have fun when we’re getting our hands dirty and mud on our boots.

References

  1. Reade, M. W. (Mike), Personal communication. June, 2017
  2. Reade, M. W. (Mike) and Becker, T. L. (Tony), Fundamentals of Pedestrian/Cyclist Traffic Crash Reconstruction, Institute of Police Technology and Management (IPTM), Jacksonville, FL 2016
  3. Civil litigation, forensic engineering and motor vehicle accident reconstruction.  Published September 22, 2015
  4. Is your traffic accident investigator well trained, experienced and “accredited”?  Published February 23, 2016
  5. “Seeing is believing” at a meeting of traffic accident investigators.  Published March 4, 2016
  6. If you  can measure it you can manage it, even if it’s a real mess like a car or truck accident.  Published June 23,, 2016
  7. Forensic assessment of traffic accidents.  Published October 26, 2016

 

What guides the ‘rhyme or reason’ of forensic engineering investigation?

What guides civil engineers carrying out a forensic investigation?  What ensures we do thorough work and give an objective opinion – in keeping with the requirements of the judicial system?  There’s usually little on this in the Appendix of an expert’s report so you could be excused for wondering.

There are, in fact, excellent guidelines in place and some are well thought out after decades of development.  They ensure the judicial system is well served.  And they’re enhanced by rules-of-thumb like the following picked up by experienced engineers over the years.

  1. Follow the evidence – an old chestnut that – for certain evidence that leads to follow-up investigations
  2. If you need more data, get it
  3. If in doubt, go deeper, particularly if the foundation soils are involved in a failure
  4. Expect the unexpected
  5. Beware the tyranny of the obvious when determining the cause of a failure
  6. Get your hands dirty and mud on your boots – get out on the site of a failure; no excuses
  7. If you can measure it you can manage it, particularly if the failure involves the natural environment as well as the built environment

I thought to mention the existence of guidelines to advocates and adjusters for a while now, particularly when a client is retaining an expert for the first time.  Also when the failure is small or medium sized as most are – not catastrophic and newsworthy – and the budget is small.  The standards are high regardless the size.

I looked through my library and found about three and a half dozen books that have guided me carrying out forensic investigations over the years.  Your eyes might glaze over at such a list.  But take a look at the following selection and be assured that civil engineers are being well guided, particularly by the literature from ASCE and SEAK.

The American Society of Civil Engineers (ASCE) has been guiding civil engineers in practice since about 1857 – 160 years – longer than Canada’s 150 years!  SEAK has been reviewing 1000s of case histories involving experts for more than 30 years, learning from what they read and passing it on to experts.  There’s a lot of guidance out there and a high standard set for civil engineers.  You can see it in the titles of the following::

  1. Lewis, Gary L., Editor, Guidelines For Forensic Engineering Practice, 2nd edition, American Society of Civil Engineers, ASCE, Reston, Virginia 2012
  2. Greenspan, Howard F. et al, Guidelines for Failure investigation, ASCE, Virginia, 1989
  3. Janney, Jack R., Guide to Investigation of Structural Failures, 2nd edition, ASCE, Virginia, 1986
  4. Ratay, Robert T., Forensic Structural Engineering Handbook, McGraw-Hill, New York 2000
  5. Nicastro, David H., Editor, Failure Mechanisms in Building Construction, ASCE, Virginia, 1997
  6. Noon, Randall K., Forensic Engineering Investigation, CRC Press, Inc., Boca Raton, Florida 2000
  7. Mangraviti, Jr., James J., Babitsky, Steven and Donovan, Nadine Nasser, How to Write an Expert Witness Report, 2nd edition, SEAK, Inc., Falmouth, Mass. 2014
  8. Zinnsser, William K., On Writing Well: The Classic Guide to Writing Nonfiction, 7th edition, Harper Collins, New York 2006
  9. Roberts, Donald V., Expert: A Guide to Forensic Engineering and Service as an Expert Witness, Association of Soil and Foundation Engineers, ASFE, 1985
  10. Speight, James G., The Scientist or Engineer as an Expert Witness, CRC Press, Boca Raton, Florida 2009
  11. Cohen, Kenneth S., Expert Witnessing and Scientific Testimony, CRC Press, Boca Raton, Florida 2008
  12. Babitsky, Steven and Mangraviti, Jr., James J., The Biggest Mistakes Expert Witnesses Make and How to Avoid Them, SEAK, Inc., Falmouth, Mass., 2008
  13. Stockwood, Q.C., David, Civil Litigation, 5th edition, Thomson Carswell, Toronto 2004

I don’t expect you to check out these references too thoroughly, certainly not read them. Just know that civil engineers are guided by good literature on how to carry out thorough forensic engineering investigations and render objective opinions.  And experienced engineers have their rules-of-thumb.

A thought: What guides your expert carrying out a forensic investigation in their field of study if s/he is not a civil engineer?