Civil litigation, forensic engineering and motor vehicle accident reconstruction

You might be interested in CATAIR, the Canadian Association of Technical Accident Investigators and Reconstructionists.

It’s quite a mouthful but members of this national group do exactly that – figure out why and how a traffic accident happened, reconstruct it.  Not too much different than figuring out why a building, bridge or mall collapsed or a person slipped and fell.  The objectives are the same, the techniques are different.

This type of person – a reconstructionist, could show up in your civil case, engineering investigation or insurance claim’s file. One did on an engineering investigation of mine.

I attended the first session Sunday evening of CATAIR’s annual, week long AGM at the Holiday Inn, Halifax.  The meeting is held in conjunction with a five day advanced collision reconstruction course.  Getting familiar with new technology – a “silver box” in this case, to collect data on a collision from a vehicle’s black box.

An estimated 22 people will take the course.  They come from across Canada and several U.S. states.  I spoke with fellows from South Carolina, British Columbia, Alberta, Ontario and New Brunswick. Another is up from Missouri.  The course is being given by a well regarded chap from Maryland.

Similar groups exist in the U.S. but they are not national in scope – and a bit international, like CATAIR.

Many of the people taking the course are police officers or were at one time.  Some others are private consultants – engineers and technologists of various stripes. Almost all investigate and reconstruct motor vehicle collisions.  One, the chap in N.B., has gone on to educate truck fleet owners on avoiding collisions.

These people are very busy.  The officers from Alberta and Ontario reconstruct collisions full time – no foot or car patrols for them.  Not surprisingly, considering that there are approximately 3,000 motor vehicle fatalities in Canada each year and 15 times that in the U.S. Then there are the serious injury accidents that are investigated and reconstructed.

I was introduced to the group by engineering colleagues of mine, private consultants Dr. Stu Smith, Cliff Tyner and Al Tupper who reconstruct motor vehicle accidents.  Ken Zwicker, President of the Atlantic provinces chapter of CATAIR, also a private consultant and former RCMP officer, has been quite supportive of my interest in the group.

My interest in CATAIR and accident reconstruction stems from my interest in different engineering and scientific investigative procedures and techniques and their application to forensic engineering.  I was quite impressed a couple of years ago when I learned from Stu and Al of the quite rigid testing and analysing carried out in motor vehicle accident (MVA) reconstruction.

I investigated the cause of the John Morris Rankin fatal MVA a few years ago for the RCMP.  I realize now that the police at the time gave me the results of a collision reconstruction by one of their own.  Basically a description of the accident and the vehicle speed at the time.  I was asked to establish if the pile of salt on the highway contributed to the accident.

I did this with full scale field testing – similar to that done in speed bump design, using the same type of vehicle driven by Mr. Rankin, a Toyota 4-Runner.  I filmed the testing and this filming was key to demonstrating the contribution.

There are different types of accident investigation – police, insurance and workman’s compensation to name three.  The results of collision reconstruction could contribute to any one of them:  And show up in your civil litigation case or insurance claim’s file, as one did in mine.



Counsel, tell your expert about the Rule governing expert opinion. It’s important

Make sure your expert knows about this Rule before he starts his investigation. Particularly the sub-section on the content of an expert’s report. (Ref. 1)  Abiding by the Rule, as required by the judicial system, may increase the time spent gathering data – the forensic engineering investigation, and also the time spent analysing the data and writing the report.  Increased time means increased cost.

This is possible – higher costs, for the small to medium size forensic investigations typical in Atlantic Canada and I suspect across the country.  Certainly when these investigations are complex.

Experts are unlikely familiar with the Rules in the same way that lawyers are unlikely familiar with the expert’s field of practice.

Engineers sometimes investigate a failure or an accident and report the cause but stop short of a detailed description of what they did.  Particularly the technical analysing and reasoning lest counsel’s eyes glaze over.  Many lawyers just want an answer – “and spare me the details”.  This might be the case when the engineer is retained as a consulting expert rather than a testifying expert.

Knowing about the Rule and that it requires more comprehensive reporting doesn’t mean estimating the cost of the forensic investigation is any easier. (Ref. 2)  It just alerts counsel and the expert to the information that must be reported and that costs may be higher.

1. Things leading to the opinion

The expert’s report, according to the Rule, must include everything the expert regards as relevant to the expressed opinion.  This approximates a full engineering report.

Everything means that the report contains all of the following information to support the opinion (I have expanded and added to the statements in the Rule according to how engineers investigate failures and accidents):

  1. Identify and describe in detail the steps and tasks carried out during the investigation and the purpose of each.
  2. Describe any research carried out.
  3. List and describe the data obtained from each task.
  4. Analyse the data from each task and any research – its nature, what it means, how the data from the different tasks are related to each other, and how each is related to the failure or the accident.
  5. Fully explain the reasoning leading to the opinion.
  6. Describe a test(s) to formulate or confirm the opinion.
  7. State the degree of certainty with which the opinion is held.
  8. State any qualification put on the opinion because of the need for further investigation or for any other reason.
  9. Reference all the literature and other material consulted in arriving at the opinion.
  10. List the documents and other information acquired to prepare the opinion.

This is comprehensive reporting.  It takes time and it can be expensive particularly in a complex case.

2. Things leading to a different opinion

But the Rule also requires that the expert’s report draw attention to anything that could reasonably lead to a different conclusion.  If “drawing attention” to “anything” means identifying and investigating other interpretations of the data, or follow-up investigations, then including the listed information on these things takes time.  It may not mean exhaustive investigating and reporting but even a little more adds to the cost of an expert’s opinion..

Experts may not expect such comprehensive report requirements. It’s important to give an expert a heads-up at the time he is being retained and before he starts his investigation.  I was given a copy of this rule by counsel shortly after it was published – after I had carried out a forensic engineering investigation but before I had written my report.  It turned out okay but we like to know about such requirements before we start an investigation.


  1. Nova Scotia Civil Procedure Rule 55, sub-section 55.04
  2. A bundle of blogs: A civil litigation resource list on how to use forensic engineering experts.  Posted November 20, 2013 (Contains blogs on estimating the cost of forensic investigations)

Why should civil litigation lawyers and experts take an interest in a book on writing well?

I suggested this in last week’s blog.  After all, lawyers are wordsmiths and experts usually have a few decades of experience so both should know how to write well.

The reason is the comprehensive requirements of the civil procedure rule governing the content of an expert’s report.  This rule does not mess around – no legalese here.  It tells experts in clear English what we are to provide the judicial system.

The reason is also the variety and complexity of the engineering problems and personal injury accidents that occur in the built and natural environments.

As a civil engineer, I know about the problems, and I read again a civil procedure rule governing experts in Eastern Canada.

Almost every case we engineers investigate – and lawyers advocate, is different from the one before, and they’re almost all complex.  Reporting on such cases to a strict civil procedure rule – and counsel understanding the report – is demanding of both expert and counsel.

Cases such as:

  • The collapse of an engineering structure, e.g., a dam, bridge, retaining wall, wharf, road, waterway, earthworks, landslide, or the poor performance of one of the structure’s many components.
  • The collapse of a building or the poor performance of one of the 100s of its components.
  • An accident causing property damage, injury or death.
  • A fuel oil spill.
  • An independent peer review of a forensic investigation and report by another.

“The same” cases are different

And when the cases are “the same” – involving one structure, a building, say, they are different.  Each one of a building’s many components can fail.

  • The leaking roofs may be flat, pitched or mansard.
  • The subsiding foundations may be a slab-on-ground, shallow footings or deep piles.
  • Flood water may be coming in through the basement walls, the floor, the utility trenches or from burst water pipes.

Or cases involving slip, trip and fall accidents – one type of accident but every case different.  The person who fell may have been,

  • Standing still, walking or running.
  • On a level or sloping surface.
  • Walking forward or backwards.
  • Walking up or down stairs.
  • Tripping on an obstacle or on their feet.
  • In their bare feet or wearing any one of a variety of different footwear.
  • On any one of many different floor or ground surfaces.

Those are some differences in just one type of structure and one type of accident. Multiply those differences by the hundreds of different structures and different accidents in the built and natural environments – and just imagine.

Everything we investigate and report on is different – every day.  In a sense, we are more “generalist” engineers as opposed to experts, at least in Eastern Canada, and I suspect elsewhere in Canada too.  But, of course, the court decides if any one of us is an expert in a given case.

No surprise then that every report we write is also different, even the simple reports.  And each must be written to the exacting requirements of rules like Section 50.04 Content of an Expert’s Report, Civil Procedure Rules of Nova Scotia.

An example might show the importance of writing even simple reports well when done according to the Rules.

I investigated the underpinning of a building a few years ago.  (Underpinning is a foundation that replaces another for some reason)  I then reported on the adequacy of the underpinning according to Rule 55 in Nova Scotia – and 30 days later got 76 questions back.

The basic forensic engineering investigation was simple.  Dig holes in the ground next to the building and expose the underpinning,  Describe, measure and photograph the type of underpinning.  Do this as well for the deficiencies in the underpinning.  Assess the adequacy of the type of underpinning and also the effects of the deficiencies.

The physical properties of a different material used in the underpinning were also researched but this went along well too.

There was also an odd side issue in the case.  The part of the building above the underpinning – what you see from the street, was not constructed properly, and in a very pronounced and unusual way. This was an even simpler investigation.  I found that the defect was unrelated to the underpinning.

The investigation and reporting were simple yet prompted 76 questions.  Some reflected the questioner’s – probably his expert’s, general lack of knowledge of the technical issues. Others were on a simple word or turn of phase.  A few were good and served resolution of the case quite well.


Writing engineering reports well is not easy – not even simple reports on simple cases. We can all use all the help we can get.  Including books on writing well.

And counsel can too, to ensure that they recognize a well written expert’s report and that they understand the technical issues – hopefully explained in simple, clear, uncluttered, jargon-free English.