In this Issue:

Common Questions Asked in Cell Phone Forensics Trucking Accident Cases
By Lars Daniels, Envista Forensics

Traffic Engineering
By Chad Zorn, CityLynx

This Issue's Toolbox Feature
Vehicle Data Download


By Lars Daniels, Envista Forensics

Trucking accidents can be catastrophic, and gathering and interpreting cell phone evidence could be critical to a case. The data may help prove what really happened and who was or was not at fault. The experts at Envista collaborated to bring you the top questions they get asked and why the answers can be so critical to a case.

What is the difference between a phone bill and a Call Detail Record?

A phone bill will contain only the most basic information. Think of call detail records as a super phone bill. It will contain extensive information not included in a standard phone bill. This information can assist an examiner in determining if there is evidence of user activity on the phone at a given time. Beware though - given the technical nature of a call detail record; this data is often misinterpreted.

Case Example:

A plaintiff attorney obtained a call detail record of the truck driver. When examining these records, they believed they had found calls occurring before and during the accident. However, upon review, experts were able to show that these were automated routing calls by the cellular service provider and had nothing to do with user activity.

What kind of data can be recovered from a cell phone if examined by forensic tools and methods?

Cell phones today contain a tremendous amount of data. This data comes in many forms. Messages, emails, call activity, videos, photos, and other forensic artifacts can be used to create a timeline of activity surrounding when an accident occurred. It is also possible to recover extensive data believed to be deleted, as well as other obscure types of data; such as if a user was using a hands-free technology while on a call, typing, searching on the phone, or watching movies.

Case Example:

When performing a forensic examination of a plaintiff’s phone, examiners were able to show that the plaintiff was taking photos of an object in the passenger side seat while driving down the road. A photo was taken seconds before impact with a truck driver.

Can data records in a Call Detail Record be used as evidence that a driver was using the phone?

With some cellular providers, when you request call detail records, they will also provide data records. An all too common claim is that these data records indicate that the user was using the phone for activity such as watching movies, listening to audio, or browsing social media.

Case Example:

Opposing counsel’s expert claimed that the driver was watching movies on his phone at the time of the accident because there were data transmissions in the call detail records at the same time. His claim was that the volume of data transmission was indicative of movies being streamed. This was speculation. One cannot determine if the data is being transmitted as an automated function of the phone, and by examining the driver’s cell phone itself, no evidence was found of the driver watching movies or doing anything else with the phone around the time of the accident.

Why Do You Need an Expert?

Some experts help win cases and some help lose cases. With people’s lives on the line, it’s important to have experts that you can trust, with extensive court testimony experience. In many cases that we’ve seen, user activity has been a hot topic of debate, as well as misinterpretation of call detail records which house call attempts, voice, text and data activity, as well as cell tower information. All of this information can be extremely important when trying a motor vehicle or trucking accident case.

For more information on what Envista’s experts do, visit our website or contact us at



By Chad Zorn, CityLynx

There are three main ways that Traffic Engineering can be used in accident reconstruction and analysis:

1) Traffic Signal Light Sequences
2) Work Zone Traffic Control Analysis
3) Geometric Roadway Design

Traffic Signal Light Sequences

Traffic Signal Light Sequences can sometimes provide critical evidence determining which vehicle had the higher probability of being at fault for an accident event. Traffic signals operate on various light sequences at different times of the day.

If certain equipment is in operation, these sequences can vary depending on the volume of traffic detected. For example, knowing which turning movement preceded a through movement can indicate who may have run a red light. Also, knowing the length of the yellow time may indicate if a “dilemma zone” is present. This is a term used to describe a point in time where a vehicle has to either speed up to beat the red light, or hit the breaks to prevent running the red light.

Sometimes, in order to properly understand what happened during the course of an accident, it may be necessary to investigate to a given traffic light to see if it has been properly maintained and therefore executing proper signal timing

Work Zone Traffic Control Analysis

Work Zone Traffic Control Analysis in traffic engineering can help determine if the proper traffic control signs and equipment were installed on a roadway as required by law.

Traffic control requirements are governed by the MUTCD (Manual of Uniform Traffic Control Devices), local laws, and local agency permitting requirements. Traffic Control must be installed as per a traffic control plan that is sealed by a professional engineer, which in turn is used to obtain a lane closure permit from a local agency. Understanding the details of these requirements may shed light on whether any party is at fault in the event of an accident in a work zone.

Geometric Roadway Design

Geometric Roadway Design involves an understanding of items such as pavement surface, sight distances, regulatory sign placements and roadway geometry. Analyzing the details of these items may indicate if a section of roadway does not comply with Federal, State or local roadway design requirements such as those listed in the AASHTO Green book or the Roadside Design Guide Manual. For example, perhaps a sign is in the wrong location, or perhaps signal equipment is missing at the back end of a sharp curve where there is not enough sight distance. Either of these could increase the chances of a vehicle collision.

Having an understanding of these Traffic Engineering concepts and being able to integrate them into your analysis and investigations can be a critical difference-maker to forensic engineers or reconstructionists. Chad Zorn is a part of the ATA Transportation Team. If you have an intersection accident, call us. We would be happy to share our expertise.


This issue’s featured topic for ATA’s Toolbox is Vehicle Data Download. Retrieving data from Vehicle Crash Data Recorders (CDR) can be a highly specialized and difficult process. We have a long history of activity in this forensic discipline which includes the recovery of air bag deployment data, gathering of speed and braking data and many other pieces of potentially critical information.

Visit the Toolbox. Then click on the Vehicle Data Download drawer. Of course, you’re welcome to explore any other drawer that might be of interest.