Expertly Speaking


Industry Update: Electronic Logging Devices in Commercial Trucks

R. Scott King, BSME, Automotive / Mechanical Engineer ::::

In March 2017, we provided an industry update on a December 2016 ruling mandating the use of electronic logging devices (ELDs) in commercial trucks ( Set to become effective on December 16, 2017, this ruling establishes data recording criteria which, in general, require truck owners to install new equipment capable of detecting and recording changes in driving status and provide law enforcement a means of easy data access. Since becoming law, the trucking industry has been preparing for the looming December deadline, with many trucking companies already compliant. However, on July 17, 2017, the House Transportation Committee attached additional requirements to the 2016 ELD mandate that could delay, or even repeal it.

The rationale for this latest development includes lingering trucking industry concerns over the potential for individual states to implement mandated rest and meal times as well as enforcement, cyber-security, and connectivity concerns. The committee also expressed its own concerns over what the financial burden compliance may place on smaller trucking companies. Our research shows that of the estimated 1.2 million registered trucking companies in the US operating an estimated 15 million trucks (approximately 90% own six or fewer trucks – all of which would be required to purchase), install and maintain these new devices. With a fleet-wide projected implementation cost of nearly 2 billion dollars, the cost of compliance to smaller trucking companies, and in particular, individual owner-operators will be significant.

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On the Speaking Circuit

Justin P. Schorr, Ph.D is scheduled to be a speaker, as well as a panel moderator, for several presentations on Autonomous Vehicle Technology. Dr. Justin Schorr is a post-doctoral researcher and adjunct professor at George Washington University (GWU) teaching Sustainable Urban Dynamics and Intelligent Transportation Systems. Justin’s first exposure to autonomous vehicles came when he was a researcher for the National Crash Analysis Center headquartered at GWU. He eventually became the lead researcher at the vehicle instrumentation and driver simulation laboratory in the Center for Intelligent Systems Research at GWU. Justin went on to teach the Intelligent Transportation Systems class to both graduate students and undergraduate students at GWU. Justin has also published papers on Autonomous Vehicles including a paper in the peer reviewed Journal of Intelligent Transportation Systems. As an engineer with DJS Associates, Justin provides expert analysis to law firms, insurance companies and government entities for collision reconstruction, highway safety, traffic and transportation matters, as well as autonomous vehicle technology. Dr. Justin Schorr can be reached via email at or phone at 215-659-2010.

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Every Minute Counts: The Importance of Emergency Warning Placement

Leslie E. Lovre, Technical Assistant ::::

Federal motor carrier safety regulations require commercial trucks to carry emergency flares or reflective triangles. When a commercial truck becomes disabled on a public roadway, the truck operator is required to place those warning devices at specified distances behind the truck and to do so within ten minutes of becoming disabled. This, of course, is intended to reduce the risk of a subsequent collision.

Over the years, our engineers have evaluated numerous collisions involving disabled commercial vehicles. We are typically asked to evaluate the reason for the disablement; however, we are also often asked whether there exists any means to determine if the emergency warnings were placed within the required ten minutes. Historically, these were hard questions to answer, if not impossible. More recently, however, on-board technology such as engine control modules and GPS devices have provided data relative to when a vehicle became disabled. Yet, there remains no built-in method to document when the warnings are placed, leaving this answer subject to witness recall and testimony. However, if a driver could also take a photograph of the triangles or flares with his or her cell phone immediately after placing them, then send that photo in an email or text message, the meta-data from the photo or message would document the placement time which, together with other on-board truck data, could establish a definitive timeline between the placement and disablement. Many trucking companies provide emergency training protocols, but in our experience, adding a simple step of photographing warnings placement could save substantial investigative resources later on.

For additional information on DJS’ Automotive Capabilities, contact Leslie E. Lovre, Technical Assistant, at or via phone at 215-659-2010.

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Child Safety Seat Fails to Deliver Safety

John R. Yannaccone, PE, Senior Mechanical Engineer ::::

Case Synopsis: A vehicle stopped at a red light was struck from behind by another vehicle. The impacted vehicle had three adult occupants, and a child harnessed into a rear facing infant seat. During the crash, it was reported that the carrier portion of the infant seat (with the child in it) separated from the installed base. As a result, the child and the carrier moved inside the vehicle and the child struck their head and sustained skull fractures with an underlying brain injury. None of the other occupants had any serious injuries.

Expert Analysis: At the time the expert was retained, both vehicles were no longer available; however, there were sufficient photographs for a reconstruction to determine this was a moderate severity collision. The child seat was available for inspection and there were generally no signs of any substantial loading to the base or the carrier, which is consistent with it not being restrained during the crash. There were some areas of minor material deformation in an area that should not have been loaded.

The mother testified she installed the child seat, and the carrier was latched into the base on the day of the incident. She had no idea why the carrier would not have been attached to the base at the time of the collision.

An exemplar child seat, the same design as the one in the crash, was used for an analysis and showed that the carrier was misaligned with the base. It was possible to have the attachment hooks contact the area, not intended for latching, which showed the minor deformation. If this occurred, it would appear to the user that the carrier was latched to the base, and capable of taking the type of loads a parent would apply to verify the base and the carrier were attached; however, it would be unable to carry the loads of even a moderate crash.

By making very minor modifications to the carrier, this additional location where the attachment hooks could improperly attach could have been eliminated. This would leave only the appropriate locations for the hooks to engage thereby preventing the risk of a false latching between the carrier and base from occurring.

Result: A case was pursued against the child seat manufacturer for the design of the child seat, which allowed the carrier to be installed in this improper position such that it was unable to sustain the loads of a crash. The case settled prior to trial.

John R. Yannaccone, PE is a Senior Mechanical Engineer with DJS Associates and can be reached via email at or via phone at 215-659-2010.

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At Odds: A Disagreement Between a Subcontractor and a Homeowner

Bryan J. Smith, PE, CFEI, Construction Site Safety Consultant ::::

Case Description/Summary: A concrete subcontractor was hired by a homeowner to replace a concrete patio, driveway, sidewalk and steps at the home. Prior to completing the work, the homeowner decided that the subcontractor’s work was sub-par and threw the subcontractor off the property and withheld the final job payment. The subcontractor subsequently sued to retrieve the earned compensation. The homeowner counter-sued for defective and incomplete work.

Expert Analysis: A site survey was performed to document the site conditions at the property. Several shrinkage cracks were found in the concrete driveway. It was determined that the shrinkage cracks were due to missing contraction joints; however, the homeowner admitted that she threw the contractor off of the property just when he attempted to saw-cut the joints. One saw-cut joint was poorly aligned with the edge of slab at the rear patio. Three expansion joints were missing at front and rear sections of pavement. The homeowner alleged that in addition to these defects, the garage door lock could not be latched because of an incorrectly sloped apron and the interface between the new rear patio and the existing upper deck support post foundations were ugly.

A field evaluation report was issued, which determined that the homeowner was responsible for the missing contraction joints and the resulting cracks. The “ugly” concrete interface was due to incomplete work (due to being thrown off the job prematurely) and a misunderstanding between the parties on how these junctions were to be addressed. The issue with the garage door lock/latch was caused by an improperly adjusted latch mechanism and not by the concrete apron under the door. The missing expansion joints could be made retroactively for well under $1,000. The one poorly aligned saw-cut joint could be filled with caulking of the same color as the concrete to mitigate the aesthetic impact.

The homeowner hired an engineer and a contractor in an attempt to refute the submitted evaluation report. Their mutual recommendations included the removal and replacement of all the work performed by the subcontractor for a cost at over 35% of the original cost. No agreement was reached between the parties and a trial ensued. Trial testimony was offered and the jury decided in favor of the subcontractor.

Bryan J. Smith, PE, CFEI, is a Construction Site Safety Consultant with DJS Associates and can be reached via email at or via phone at 215-659-2010.

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Was A Gas Line Explosion Accident Foreseeable?

Johann F. Szautner, PE, Civil Engineering Consultant ::::

The Accident: A municipality in Pennsylvania hired a contractor to install a concrete sidewalk, a concrete curb, and to replace stormwater collection inlets in and along an existing paved municipal street. Prior to commencing construction, the contractor made the required PA-1 call to ascertain the location of underground utility lines within the excavation limits. A storm sewer pipe running along the edge of the pavement, and a gas service line crossing it were located and marked properly. As the backhoe operator peeled off a portion of the pavement, the spotter, who walked alongside the backhoe, saw the yellow gas line, and yelled a stop command to the operator. The explosion occurred immediately, where the gas line entered the building, destroying the building, which was unoccupied at the time. Thankfully, only property damages resulted from this accident.
The Regulations and Best Practices:

Code of Federal Regulations, 49CFR192.361 requires that a gas service provider install a service line with at least 18 inches of cover in a public right-of-way, and with at least 12 inches of cover on private property. However, where an underground structure prevents installation at those depths, the service line must be able to withstand any anticipated load.

PA Underground Utility Protection Act 121, P.L.852, No.287 requires that contractors use prudent techniques, including hand digging or vacuum extraction to determine the exact location of a marked facility within the tolerance zone.

CGA Common Ground Alliance Best Practices were issued by a USDOT task force to provide a construction guide for the prevention of underground utility damage. This guide stipulates that hand digging and non-evasive methods are not required for pavement removal.

The Investigation: During the investigation, it was found that the gas distribution line was at a depth of 6 feet, and the service line rose from this depth to within 7 inches of the pavement surface near the right-of way line. The top of it was partially encased by the pavement. The subject gas service line was installed in the early seventies, to replace the original but corroded service line. The replacement service line was raised to this height to cross over a 24-inch diameter storm sewer pipe, which was installed by the municipality over the original gas line. However, the replacement service line could have been easily installed by laying it under the storm water pipe, or alternatively by protecting it from displacement with a concrete encasement.

It is not uncommon that gas pipes are not in marked locations, and the contractor who contractually assumes the risks associated with excavating a gas line, must always proceed with due care assessing foreseeable risks. But what if a gas line is installed negligently, and in violation of pertinent regulations? Is this a situation a reasonable contractor can foresee and therefore should be held liable? Or is it a situation where the utility owner knew or should have known about the faulty installation and then be jointly liable for damages?

The Outcome: The litigation was resolved by a jury trial finding the contractor 100% liable.

Johann F. Szautner, PE is a Civil Engineering Consultant with DJS Associates and can be reached via email at or via phone at 215-659-2010.

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