Archive for November, 2008

Contributing Factors: The T-Bone

Friday, November 7th, 2008

There are a wide variety of contributing factors associated with vehicle accidents, and careful analysis is required to fully and accurately determine fault because of these many factors. For instance, let’s consider the case of a “T-Bone” type collision.

In this hypothetical collision, there is a Chevrolet traveling south on Hwy 11 when a Nissan pulls out from a side road into the path of the Chevrolet, and the Chevrolet impacts into the passenger side of the Nissan. Who is at fault in this collision? That can depend on several factors. Below is a partial list of possible contributing factors for each vehicle.


Nissan Chevrolet
Disregarded a Stop Sign Speeding
Failed to Yield the Right of Way Inattentiveness
Headlights Not Illuminated Headlights Not Illuminated

Only through a careful and thorough investigation can fault be accurately assigned. Our accident reconstructionists can typically confirm or disprove which of these were in fact the cause(s) of the accident. The following are various questions about contributing factors that you might have and the corresponding methodology we have available to answer those questions.

Question: Did the driver disregard the stop sign?

Answer: Based on impact speed and acceleration calculations we can determine whether it is reasonable for a vehicle to reach its speed after stopping at the stop sign.

Question: Was the vehicle speeding?

Answer: We can do various calculations to determine speed based on damage patterns, departure angles, and final rest locations. Also, we may be able to download crash data recorder information that can answer this question.

Question: Was the driver paying attention?

Answer: Based on speed/time/distance calculations, we can determine the approximate location where and the time when the driver perceived the hazard of the other vehicle and began to react. Then, we can attest to whether or not this information is consistent with a typical and attentive perception and response.

Question: Were the vehicle’s lights on?

Answer: In most cases this can be determined by forensic evidence that can be documented and collected.

Other questions that we consider and have the ability to analyze and address include:

· Was fog present creating a sight distance and headlight issue?

· Did sun glare obstruct or limit the view of the driver?

· Were the ambient light conditions such that the vehicle would have been visible?

· Were the proper traffic controls in place and appropriately located?

· Did the environmental conditions call for a reduction in the reasonable speed to be traveling?

As you can see, it is not a simple matter to say one or the other party is at fault. It takes a conscientious consideration of many possible factors.

Jonathan McGehee

Decade Long Eleven State Study of Blasting Damage Claims

Friday, November 7th, 2008

 Recently, VCE Inc. completed a 10 year, 11 state engineering study of 2,250 blasting damage claims from 1999 to 2008. These investigations were made in Tennessee, Kentucky, Virginia, Nevada, California, Georgia, South Carolina, North Carolina, Alabama, Arizona and Utah. The investigations were made over the last decade and intended to determine if blasting vibrations, or other related forces, were responsible for claimed damages. It was determined that blasting damage claims resulting from ground vibrations damage are valid less than 1.3 percent of the time.

I decided to publish this information in an article in order to address a reoccurring question I have received from many adjusters and homeowners. “Does blasting ever cause damage to structures?” The details of this study and the examples of specific blasting damage and non-blasting related damage causation conditions are best detailed in a short seminar where numerous photos could be used to illustrate some of the study’s findings.

It was determined that valid blasting damage occurred as a result of impact damage associated with fly rock, air concussion stressing, instantaneous reverse stressing associated with ground vibration and crater zone soil shifting related stressing.

The majority of the claimed blasting damages were found to be caused by something other than blasting. These non-blasting causes have included constructions defects, wind damage, thermal and moisture related stressing, differential settlement or other soil related issues, cross grain contraction and seasoning of wooden members, termites, carpenter ants and other insect related wood damages, as well as hydrostatic pressure in the soil. This study examines in detail damages from fly rock, air concussion, ground vibration and soil shifting on numerous residential and commercial structures.

The study contains 1,872 blasting claims in Tennessee, a state whose geology requires blasting for most utility line installations, mass grading for site preparations, highway construction and mining. The valid blasting damage claims have occurred in vibration ranges consistent with previously documented levels for various structural materials.

The study established that valid blasting damages resulting from any direct or indirect blasting related force occur less than 3.5 percent of the time. Blasting damage occurred in the studied structures as a result of fly rock 0.27 percent of the time, they resulted from air concussion 1.82 percent of the time, they resulted from ground vibration 1.29 percent of the time, and they resulted from soil shifting within the crater zone 0.09 percent of the time. It is important to note that this study was simply based on investigations of structures that had a blasting damage claim and did not include the countless number of structures in the areas adjacent to the same blasting activities that not only did not have any damage, but who also did not file a blasting damage claim.

While blasting was not often found as a cause of damages associated with many blasting damage claims, it was on occasion responsible for the damages. Competent experts with direct experience in blasting related stresses and damage forces can identify these damages when they occur.

 Wade Hutchison