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Whether large or small, a truck fleet operator has to know the locations of its vehicles in order to best manage its business. On a day to day basis loads need to be delivered or picked up from customers, and other activities such as vehicle maintenance or repairs have to be routinely accommodated. Some fleets use aftermarket electronic systems for keeping track of vehicle locations, driver hours of service and for wirelessly text messaging drivers via cellular or satellite networks. Such aftermarket systems include GPS (Global Positioning System) technology, which in part uses a network of satellites in orbit. This makes it possible for the fleet manager to remotely view the location of a vehicle and view a map of its past route. These systems can obtain data directly from vehicle sensors or from the vehicle network, and therefore report other information such as fuel economy.

The GPS (Global Positioning System) is a navigational tool available to the public, comprising in part a network of satellites in orbit broadcasting signals to GPS receivers on earth. Due in large part to the very accurate clocks in the system, a GPS receiver that receives a number of these signals simultaneously can then establish its location on earth. Some GPS receiver models have the capability to record a history of the latitude and longitude co-ordinates at known times, and these may later be downloaded and viewed on a computer using applicable software. Effectively, this provides the equivalent of a bread crumb trail of the path taken by the receiver, although the frequency of the data points can vary substantially from one model to another, and it may not be adjustable by the user. By plotting the information on a map, the trail can be viewed and the position-time history of the vehicle may become evident.

Collision data stored in the Airbag Control Module (ACM) of some Chrysler vehicles has become available to accident investigators through the Bosch Crash Data Retrieval (CDR) system, beginning with the 2005 model year. An event data recorder (EDR) that can record pre-deployment vehicle speed and other parameters such as brake pedal application and throttle application is incorporated into the ACM, or Occupant Restraint Controller (ORC) using Chrysler terminology. The accuracy of this data under different driving conditions has not been extensively tested and reported. The primary purpose of this paper is to evaluate the accuracy of the data recorded in the Chrysler ACM under test conditions. Establishing the reliability of this information is important, if it is to be relied upon by the investigator. These results can be used to quantify the accuracy of ACM reported pre-crash data for use in engineering analysis of automobile crashes.

Electronic Control Modules (ECM) on Heavy Duty truck engines have the ability to control or monitor important engine and vehicle parameters. Examples of these parameters are fuel consumption, cruise control operation and oil pressure. Under certain conditions, many can also record parameters that are useful in accident reconstruction. Cummins engines are commonly found on highway tractors on the road today. In a heavy vehicle equipped with a Cummins engine, a hard brake application or a collision with an object can create a Sudden Deceleration Data (SDD) Report on the ECM. Since this data reports second-by-second speed information, it can be very useful in the analysis of an accident. Establishing the reliability of this information is important, if it is to be used by an accident investigator. This paper explores the data recorded on a Cummins engine ECM created during a series of acceleration, cruising, and braking tests.

The Electronic Control Modules (ECM) installed on heavy truck engines record data during normal operation. While their primary purpose is to control the mechanical and electrical systems on the engine, they monitor other vehicle systems as well. Stored data from the ECM can be downloaded into reports that are useful for tracking fleet performance, scheduling maintenance or troubleshooting engine problems. Many of the current production heavy trucks also record event information that may be useful when analyzing or reconstructing accidents. It is not uncommon for a vehicle involved in a frontal accident to experience sudden decelerations and/or sustain damage to the coolant system or rupture the oil pan. Sustained data outside normal operating parameters from sensors on the engine will typically trigger the ECM to generate a fault code. On a Caterpillar ECM, a short event record called a Diagnostic Snapshot may also be generated with a fault code.

Heavy duty truck and engine manufacturers have been installing various forms of electronic Event Data Recorders (EDRs) on their products over the past decade, the most common being the Electronic Control Module (ECM). The primary purpose of the ECM is to control electrical and mechanical systems on the engine. As well, it monitors other vehicle systems. The ECM stores data in a manner that allows reports to be generated that aid fleet managers to monitor the performance of their equipment and that assist mechanics to diagnose problems. Some of the data in these reports can be of value in accident investigation and analysis even though these reports may not have been originally intended for this purpose. This paper discusses the specifics of data collection from the various ECMs and the reliability of such data when used for the purposes of accident analysis based on testing.