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Technical Paper

Using NFPA Compliant Fire Apparatus Vehicle Data Recorders for Collision Investigation - Weldon Type 6444

Abstract The use of Heavy Vehicle Event Data Recorders (HVEDRs) in collision analysis has been well recognized in past research. Numerous publications have been presented illustrating data accuracy both in normal operating conditions as well as under emergency braking conditions. These data recording devices are generally incorporated into Electronic Control Modules (ECMs) for engines or Electronic Control Units (ECUs) for other vehicular components such as the Anti-Lock Brake System. Other research has looked at after-market recorders, including publically-available Global Positioning System (GPS) devices and fleet management tools such as Qualcomm. In 2009, the National Fire Protection Association (NFPA) incorporated a Vehicle Data Recorder (VDR) component into their Standard for Automotive Fire Apparatus. The purpose of this was to “…capture data that can be used to promote safe driving and riding practices.”
Technical Paper

Using Marine Engine Control Units in the Investigation of Watercraft Collision Incidents - Mercury Verado Outboard Engine

Abstract In the investigation of a collision involving recreational watercraft, analytical methods are generally limited when compared to incidents involving land-based vehicles. As is indicated in previous publications, investigators often rely on time/distance relationships, human factors, the matching of damage to determine vessel positioning at impact, and the recollections of witnesses. When applicable, speed estimates are generally based on the boat engine's revolutions. By considering the engine speed, the drive gear ratio, the propeller pitch, and the likely slip of the propeller, an estimation of the boat's travel speed can be made. In more recent publications, it has been recognized that Event Data Recorder (EDR) technology incorporated into various Electronic Control Units (ECUs) used in automotive applications can be beneficial to collision investigation and reconstruction.
Journal Article

Timing and Synchronization of the Event Data Recorded by the Electronic Control Modules of Commercial Motor Vehicles - DDEC V

It is well recognized that Heavy Vehicle Event Data Recorder (HVEDR) technology has been incorporated in the Electronic Control Modules (ECMs) on many on-highway commercial motor vehicles. The dynamic time-series data recorded by these HVEDRs typically include vehicle speed, engine speed, brake and clutch pedal status, and accelerator pedal position. With specific respect to Detroit Diesel ECMs, data are recorded surrounding certain events at a rate of 1.0 Hz. In this research, controlled testing was conducted to determine the time differences between the values being generated by the sourcing sensors and the interpreted data being broadcast on the vehicle's SAE J1939 controller area network (CAN). To accomplish this, raw sensor data as provided to the ECM was monitored, as were the subsequent J1939 CAN transmissions from the ECM.
Technical Paper

Empirical Testing of Vehicular Rotational Motion

Vehicles often rotate during traffic collisions due to impact forces or excessive steering maneuvers. In analyzing these situations, accident reconstructionists need to apply accurate deceleration rates for vehicles that are both rotating and translating to a final resting position. Determining a proper rate of deceleration is a challenging but critical step in calculating energy or momentum-based solutions for analytical purposes. In this research, multiple empirical tests were performed using an instrumented vehicle that was subjected to induced rotational maneuvers. A Ford Crown Victoria passenger car was equipped with a modified brake system where selected wheels could be isolated. The tests were performed on a dry asphalt surface at speeds of approximately 50 mph. In each of the tests, the vehicle rotated approximately 180 degrees with the wheels on one side being completely locked.
Journal Article

Dry Pavement Friction Reductions Due to Sanding Applications

The importance of friction applications in the field of collision reconstruction is well recognized in published research. However, tire-road frictional drag values (μ-values) are partially dependent on the surface on which the tire is travelling. One such variable may be the intentional presence of sand upon a particular roadway. Sand is sometimes applied to dry pavement in an effort to absorb liquid debris that may have been accidentally spilled onto the surface. Once the sand has been applied, it may be left for a measureable time until the fluid has been absorbed. If a collision were to occur on that particular surface while the sand is in place, it may be difficult to determine an appropriate μ-value for the given scenario. In an attempt to examine the extent of friction reduction for both a passenger vehicle and a commercial truck on such a surface, testing was performed in a like condition.
Technical Paper

An Examination of Diagnostic Event Data in Bendix Antilock Brake System Electronic Control Units

The use of Heavy Vehicle Event Data Recorders (HVEDRs) in collision analysis has been recognized in past research. Numerous publications have been presented illustrating data accuracy both in normal operating conditions as well as under emergency braking conditions [1,2,3]. To date, the bulk of this research has focused on HVEDRs incorporated into the Electronic Control Modules (ECMs) employed by various manufacturers to monitor and control engine operation. Oftentimes, data associated with engine diagnostic faults include vehicle speed and driver input parameters that are later used in a collision analysis. In addition to the ECM, other electronic control systems may store data associated with fault conditions. For example, the Antilock Braking System (ABS) Electronic Control Unit (ECU), which is tasked with electronically controlling brake application air pressure to reduce wheel lockup, is such a unit that has the ability to store diagnostic information.
Journal Article

Data Extraction Methods and their Effects on the Retention of Event Data Contained in the Electronic Control Modules of Detroit Diesel and Mercedes-Benz Engines

The Electronic Control Modules (ECMs) aboard many on-highway commercial motor vehicles contain event data useful to the investigation and reconstruction of motor vehicle collisions [1,2,3,4]. Methods of extracting such event data include: connecting to the ECMs through the vehicle's Off-Board Diagnostics Connector (a 6 or 9 pin connector typically found inside the vehicle near the driver's seat); connecting directly to any ECMs while they are still connected to the engine; and connecting directly to the ECMs after they are removed from the engine (a method typically referred to as a Bench image). This research is an attempt to document the effects of these data-extraction methods on the retention of the event data contained in the ECMs of the on-highway commercial motor vehicle engines manufactured by Detroit Diesel and Mercedes-Benz.
Journal Article

An Examination of Snapshot Data in Caterpillar Electronic Control Modules

It has been recognized that Event Data Recorder (EDR) technology incorporated into the Electronic Control Modules (ECMs) of on-highway heavy truck engines can be a benefit to motor vehicle collision investigation and reconstruction [1,2,3,4,5,6,7]. Such beneficial features include the snapshots recorded by many Caterpillar engines. These snapshots, which are triggered by engine faults, operator input, or by what is called a “Quick Stop,” record engine operation and parameters surrounding the event. Past research has reported that while snapshot data are accurate, the documented event time may be off by 24 hours in some ECMs, notwithstanding the module's clock settings being correct [7]. Furthermore, other research has suggested that some modules may report the time interval between data points at approximately two times the actual duration [6].
Technical Paper

Simulating the Effect of Collision-Related Power Loss on the Event Data Recorders of Heavy Trucks

Event Data Recorder (EDR) technology has been incorporated into the Electronic Control Modules (ECMs) of many on-highway heavy trucks. One benefit of this technology is its applicability to vehicle collision investigation and reconstruction ( Goebelbecker & Ferrone, 2000 ; van Nooten & Hrycay, 2005 ). However, collisions that cause extensive damage to the truck may cause a loss of electrical power to the ECM, which might interrupt the data storage process. This research is an attempt to determine the effects of power loss on heavy vehicle ECMs 1 , and the associated effects on data collected by the EDR function. Controlled testing was conducted with Detroit Diesel, Mercedes, Mack, Cummins, and Caterpillar engines, and power failures were created by artificially interrupting power between the vehicle's battery and ECM at predetermined intervals. EDR data from the test vehicles were extracted after each test, and the presence or absence of new data was examined.