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Understanding the role of the ‘black box’ in truck accident cases

All kinds of motor vehicle accidents can lead to serious injury, but accidents involving large trucks are especially dangerous because of their size and weight. These accidents also lead to more complex legal issues when the injured seek compensation for their damages.

In trying to uncover what caused a truck crash, investigators and others sometimes speak about a so-called black box that can reveal evidence. In this blog post, we will discuss these devices and how they might help the injured recover the compensation they deserve.

Electronic Control Module

In the context of a large truck, “black box” refers to a device more accurately known as an Electronic Control Module, or ECM. Essentially, an ECM is a small computer that is attached to a truck’s engine, and records data while the truck is in operation. The devices have been available for many years and are widely used in the trucking industry to monitor a truck’s performance, to diagnose mechanical problems and to maintain vehicles.

The ECM is sometimes likened to a commercial aircraft’s flight recorder or a passenger car’s Airbag Control Module, but this can be misleading. Flight recorders can collect a great deal of information about an aircraft’s travels and Airbag Control Modules are tied to safety features that deploy in the event of an accident. By contrast, ECMs are much more limited in what they can record and what those recordings can tell investigators about an accident.

The ECM as evidence in a personal injury case

For the plaintiff in a truck accident personal injury case, the most important thing to know about ECMs is that their data can be used as evidence. The plaintiff and their attorney should discuss seeking a protective order to preserve the ECM. Ideally, they should do this as early in the process as possible so as to make sure the relevant data is not lost or destroyed.

Once they have access to the ECM, the next step comes in accessing and interpreting its data. There are several manufacturers of ECMs, and each design works somewhat differently. Most record driving speed, braking, distance, engine rpm and other basic information. Some offer more detailed information. Most can record about 30 days’ worth of data.

The data in an ECM can’t always help determine the direct cause of an accident. It typically won’t show what caused a collision. However, it can be used in more indirect ways.

For instance, the plaintiff can compare the ECM data to the driver’s log to see if the times match. The trucking industry faces federal regulations that limit the amount of time drivers can be on the road without a break, so as to avoid dangerous fatigue. However, the tight deadlines of the industry often lead to drivers pushing their limits and then falsifying their records. A discrepancy between a driver’s log and the ECM data can indicate that the log is not accurate.