Wednesday, April 6, 2016

Case review of motorcyclist vs. utility service truck driver

Case summary:
A group of motorcyclists are traveling westbound along a winding rural highway in southern Indiana. Near the back of the group, one rider began his approach into a right curve. At the same time, an electric utility service truck traveling eastbound entered the opposite side of the curve. The motorcyclist collided with the left side of the truck. The motorcyclist survived but had his left leg detached. The truck driver was uninjured.

Wolf Technical Services was retained by the electric utility to provide reconstruction and demonstrative evidence services. Fortunately, Wolf has all of the personnel and varied expertise required to satisfy the client's needs. Bill Dickinson, P.E. was the case manager and set out to reconstruct the incident. Tim Maher was tasked to develop the extensive demonstrative evidence communication tools. Joe Hubert handled the field survey and developed the scaled vehicle models to be used on the large print exhibit.

The weather was warm and clear. The road was dry and clear.

Background and evidence:• The motorcyclist had little experience riding motorcycles.• Another motorcyclist following the subject motorcycle stated that the truck's rear wheels were on the double yellow centerline. If accurate, the truck's utility mirrors would have extended into the motorcyclist's lane. He further stated that he was only 30 to 50 feet behind and that they were traveling 25 to 35 mph.• The truck driver stated that he never left his lane and that he was driving below the speed limit. He further stated that the motorcycle crossed over the centerline before colliding with his truck.• The truck driver was qualified to drive the truck.• The truck passed the most recent annual inspection.• Law enforcement personnel took photos of the scene and vehicles.• An electric utility supervisor measured and sketched the scrapes and tire marks left from the collision. Challenges for Wolf:
• The road was paved over before Wolf could conduct a site investigation. While the new pavement and lane striping were the same, the scrapes and tire mark evidence were lost. Were the measurements taken at the time of the incident accurate?
• Is the witness account credible?
• The client wanted a high-resolution overhead photo of the site suitable for the exhibits, but none were available. How could they be obtained?
• One of the requested exhibits was a very large scaled print exhibit with scaled vehicle models that testifiers could move. There were no commercially available vehicle models that matched the incident vehicles. How could accurate models be developed?
• The client wanted video graphics (also known as trial animations) that were as realistic and compelling as possible. Traditional computer-generated movies were not adequate. What solution would work best?

Bill Dickinson analyzed the available evidence, conducted a site inspection, and inspected the motorcycle and an exemplar truck. Based upon the evidence and his analysis he came to several conclusions.

The scrapes at the point of impact and the truck's post-impact tire marks were measured and located within the truck's eastbound lane by a person who was not formally trained for the task. The site photos generally correspond to the measured location. However, Bill could not rely on the measurements without independent verification. By utilizing the science of photogrammetry, he was able to use the photos and the survey data to determine the correct location and dimensions of the marks. This data was used for his subsequent analysis, as well as for all of the exhibits.
Photographic image of collision evidence.
Photogrammetric results overlaid on photographic image of evidence.
Based upon the relative locations and the closing speeds of the vehicles, Bill determined that the witness only had between .2 and .4 seconds to see what he reported to be the truck's rear wheels on the centerline. During this time, the witness also had to maneuver his motorcycle and avoid his crashing companion. This analysis provided our client useful information for doubting the credibility of the witness statements.

As a result of Bill's analysis, he concluded that the westbound motorcycle was left of the double yellow centerline separating the east and westbound lanes when it struck the eastbound service truck. The service truck was completely in the eastbound lane when it was struck by the motorcycle.
Transparent image of truck and motorcycle overlaid on an image of the collision scene evidence show relationship of vehicles to centerline at impact.
Illustration showing relationship of the motorcycle and the REMC Service truck to the double yellow center line on the highway at the time of collision

Exhibit development:
To obtain the needed aerial photo, the electric utility provided a boom truck and operator to lift Tim Maher sixty feet above the site where he took several photos from different positions. Back at the office, and using Joe's site survey data, he accurately blended multiple photos into one seamless aerial image that was then used for the exhibits.

The client asked for a large print of the aerial exhibit along with matching vehicle models. The final mounted print is 15 feet wide by 5 feet high (stop by our offices to see it displayed). Joe Hubert prepared the models. Because there were no commercially available models that matched, Joe combined closely matching models with parts printed using our 3D printer along with his custom crafted components. The results were accurate and realistic representations of the original vehicles.
Image of scale model exhibit with scale vehicles located at the collision area.
Image of the large scene exhibit.
Finally, to provide the client with the highest realism in trial animations, Tim developed a series of HyperVideo portrayals. He worked under the direction of Bill while incorporating the site survey and reconstruction data to ensure the portrayals faithfully represented Bill's opinions. These video graphics blend site video with realistic computer-generated vehicles and provide a robust communication tool to support Bill's testimony. A collection of the videos for this case can be seen on our YouTube channel.

Our work significantly facilitated our client's negotiation of a very favorable settlement.

Urgent Evidence Preservation Services

Wolf recognizes the critical importance of evidence for civil and criminal litigation. To ensure evidence is available for immediate or future analysis this preservation must be timely and deliberate. We understand the implications of evidence spoliation and the importance of maintaining the chain of custody.

We are available to act promptly to preserve evidence. We have trained and experienced crews available to travel on short notice. We possess the knowledge and resources to ensure evidence is preserved for immediate or future analysis.

Wolf uses established evidence protocols for collection, processing and storage. We have dedicated and secure evidence storage facilities.

Limitations of Event (Crash) Data Recorders

While data from Crash Data Recorders, also known as EDRs (Event Data Recorders), can be significant for accident reconstructionists, it has its limitations. In this report we study several cases where this data could be deceptive without considering all of the available evidence.

Case #1: This example involved a full-size pickup truck that was involved in a parking lot collision with a car. The damage to the pickup was not severe. Its airbags did not deploy and the pickup was driven from the scene. Sometime later the data was extracted from the pickup’s EDR and it showed a single non-deployment event that had occurred while the pickup traveling at more than 50 mph. It also showed the throttle was in the idle position, although the engine rpms were above idle, and the driver did not have the brake applied. Some time passed before the data was extracted and it could not be ascertained that the recorded event occurred on the same ignition cycle as the collision. Because the damage to the vehicles was not consistent with a 50 mph collision and the parking lot was not large enough for the pickup to have accelerated to that speed, it was concluded that the recorded event was not associated with the parking lot collision. The driver of the pickup stated that the pickup had not been involved in any other collisions. The most likely explanation is that the pickup had hit a chuckhole while traveling at highway speed.

Case #2: Wolf staffers investigated an incident where two vehicles collided at an intersection in which the traffic signals were not functioning due to a local power outage. The front of a green compact sedan struck an SUV on the right side causing both vehicles to travel diagonally out of the intersection. The SUV then collided with one corner of a brick home in that quadrant of the intersection. The air bags in the SUV did not deploy either when it was struck on the side or when it struck the building. However, its EDR had recorded data for two non-deployment events. The recorder indicated that there were other non-deployment events, but data from those events was not saved due to lack of storage capacity. Data for the first stored event indicated that it occurred while the vehicle was traveling at 48 mph. The SUV could not have been accelerating from rest to 48 mph in the too-short distance it traveled from the stop bar to the area of impact. On the other hand, if that 48 mph event was associated with the intersection collision then it would be clear evidence that the driver of the SUV did not stop before entering the intersection (as required by law when the traffic signals are not working). Therefore, if only the EDR data were considered, it would appear that the SUV driver was at fault.

A more complete reconstruction based on the rest of the available evidence and a more complete analysis of the EDR data showed that for several reasons, the first recorded non-deployment event (at 48 mph) could not have been associated with being struck by the sedan in the intersection. The data for the second recorded event was a good match with other evidence concerning the later collision with the house. Based on the all the information, we concluded that the SUV’s speed at impact was consistent with the driver stopping and then accelerating into the intersection. It was clear from the reconstruction that the driver of the sedan had not reduced her speed as she entered the intersection.
Case #3: In a case involving a collision at a T-intersection, an initial review of the imaged data and the police report suggested that the driver of a white van traveling on the through street had begun to react approximately 5 seconds prior to impact and had nearly stopped prior to colliding with a late model SUV making a left turn from the side street. The data from the left turning vehicle showed that its driver had made a “rolling stop” and then accelerated as the driver made the left turn. None of the air bags in either vehicle deployed, but both EDRs contained post-impact data for a non-deployment event. A non-deployment event is a crash whose severity exceeds a minimum needed to cause the EDR to create a record, but whose severity is below the threshold needed to command deployment of the air bags.

An investigation at the collision site revealed two important factors that enabled Wolf’s analysts to correctly interpret the data obtained from the EDRs. First, the sight line at the intersection was severely limited by some vegetation which would have made it impossible for the driver of the vehicle on the through street to see the other vehicle 5 seconds before they collided. Second, after clipping the turning vehicle the first vehicle went off the road and over a tall, steep embankment into a creek. With this new information, we concluded that the fall into the creek was the likely non-deployment event that was recovered from the recorder. The collision with the SUV most likely also triggered recording of a non-deployment event, however the data for the initial non-deployment event would have been replaced by data from the second since the EDR in this particular van model was only capable of storing data from the most recent non-deployment event. Working back from where the vehicle came to rest, our reconstruction led to the conclusion that the van had been exceeding the speed limit by about 10 mph and that braking began just a short time before impact occurred.
In summary, while the data from an event recorder may provide valuable information, it should always be considered in conjunction with a thorough analysis of all the other available information. Several members of the Wolf staff have training in the analysis of data from event recorders and can provide you valuable assistance in making sure you see the whole picture.

Lost Photo Evidence: Why Experts Need the Original Digital Photo

For a recent construction zone accident investigation we were asked to determine the location of one of the construction signs from the one available site photo. The photocopy we were provided was destructively modified. It was first printed to paper, and then scanned to a gray-scale low-resolution .pdf file (see below). Unfortunately, in the resultant image, some important details were lost.

Wolf Civil Engineer Ben Hosinski, P.E. was trying to conduct a field photogrammetric analysis but was unable to locate two apparent poles in the background. Eventually he was supplied the original and unaltered digital image file where he could see that the two poles were part of another temporary construction sign. So much data was lost in the first file that the sign itself could not be seen.

The unaltered file also included the photo’s metadata that was lost in the modified version. This data documents the conditions under which the media was created. Metadata may include date, equipment model, equipment settings and more. Analysts need this data to know under what conditions the recording was created. James Sobek, Wolf’s senior visibility consulting expert, explains that photo files “... contain metadata information as to actual time that each image was taken and the ISO, relative aperture (f/) setting and the exposure time for each shot. That will allow me to independently assess lighting levels.” Metadata documenting flash use is also available. Using a flash in nighttime shots provides false illumination that alters the actual conditions at the time of an incident.

Finally, the modified file would make a very poor courtroom display for jurors trying to understand what happened. The unmodified version had all the quality needed to make an exhibit that would display well from a large format TV, projector or large print.

Friday, December 6, 2013

Wolf Graphics

The Wolf Technical graphics team can make the complex understandable. In fact, the level of realism for HyperVideo is so high that viewers become virtual witnesses to the event. 

Tuesday, July 2, 2013

Photographing Fireworks (Low Light Photography Tips)

By: Jim Sobek, P.E., Visibility & Lighting Expert

July 4th will find hundreds of thousands of people watching fireworks displays. Some will want to take photographs and most of those photographs will "come out" poorly because the photographer let the camera "do its thing." Here are a few tips to capture the magnificence of the evening.

Monday, June 24, 2013

Presentations and Seminars

Let us know if we can ever help with content for your seminars. Some of our presentation topics from past seminars are: