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Recovery of snapshot data recorded by Caterpillar engine control modules (ECMs) using Caterpillar Electronic Technician (CatET) software requires a complete snapshot record that contains information gathered both before and after an event. However, if an event is set and a crash ensues, or a crash creates an event, then it is possible for the ECM to lose power and not complete the recording. As such, the data may not be recoverable with CatET maintenance software. An examination of the J1708 network traffic reveals the snapshot data does exist and is recoverable. A motivational case study of a crash test between a Caterpillar powered school bus and a parked transit bus is presented to establish the hypothesis. Subsequently, a digital forensic recovery algorithm is detailed as it is implemented in the Synercon Technologies Forensic Link Adapter (FLA).

Vehicles using controller area networks (CANs) for on-board device communications may have event data recorders (EDRs) that either capture or reflect network feeds from an array of sensors and other electronic control units. Using the data recorded in an EDR for investigative purposes requires external verification of accuracy. However, conducting external tests that set events can be expensive due to the time and equipment involved. This paper proposes a practical verification method that uses CAN bus monitoring tools to compare vehicle network traffic to external measurements. The premise of this work is that data reliability from an EDR can be determined if the reliability of the network data source for the EDR can be determined. Once the reliability of the source is determined, the reliability of the event data can be quantified based on effects of truncation and sampling.