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The use of the United States’ Global Positioning System (GPS) to assist with the management of large commercial fleets using telematics is becoming commonplace. Telematics generally refers to the use of wireless devices to transmit data in real time back to an organization. When tied to the GPS system telematics can be used to track fleet vehicle movements, and other parameters. GPS tracking can assist in developing more efficient and safe operations by refining and streamlining routing and operations. GPS based fleet telematics data is also useful for reducing unnecessary engine idle times and minimizing fuel consumption. Driver performance and policy adherence can be monitored, for example by transmitting data regarding seatbelt usage when there is vehicle movement. Despite the advantages for fleet management, there are limitations in the logged data for position and speed that may affect the utility of the system for analysis and reconstruction of traffic collisions. The U.S.

Traditional accident reconstruction analysis methodologies include the study of the crush-energy relationship of vehicles. By analyzing the measured crush from a vehicle involved in a real world accident and comparing it to a test vehicle with a known energy, from a crash test, the real world vehicle's damage energy can be evaluated. In addition, the change-in-velocity (Delta-V) can be calculated. The largest source of publicly available crash tests is from the National Highway Traffic Safety Administration (NHTSA). NHTSA conducts numerous Federal Motor Vehicle Safety Standard (FMVSS) compliance and New Car Assessment Program (NCAP) testing for many passenger vehicles for sale in the United States.

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.

Heavy trucks can have the capability to record vehicle status and performance data. In many applications, this capability is intrinsic to the powerplant’s electronic controls. However little information has been published regarding Heavy Vehicle Event Data Recorder (HVEDR) data obtained from Mack trucks equipped with the V-MAC vehicle electronic control units. This study is focused on data from Mack trucks and the influence of wheel slip on the HVEDR-reported vehicle speed. Additionally, the influence of variables such as initial speed and loaded condition are discussed. A late model Class 8 Mack was instrumented with a calibrated data acquisition package (DAQ) and put through a series of tests so that the HVEDR data could be compared to the data collected by the DAQ.

Vehicle to vehicle sideswipe collisions may involve contact between a vehicle body and a contacting vehicle's rotating wheels, tires and lug nuts. During a sideswipe collision between a truck and an automobile it is not uncommon to see lug marks in the shape of consecutive damage loops or strikes on the side of the impacted vehicle. The damage loops or strikes are generated by the protruding lug nuts of the truck wheel as it passes by the impacted vehicle at a shallow angle. Additionally, rubber transfers due to contact with the tire sidewall and metal scraping from the wheel rim also leave distinctive shapes on the sides of the contacted vehicle body. The tire, rim, lug nut markings and associated damage manifest themselves as a special case of the epitrochoid and can be geometrically and mathematically described. Presented is a derivation of the equations that govern the lug, rim and tire positions and relative motions.

The technology of exterior automotive lighting is undergoing the first major change in a half-century. Manufacturers of road vehicles, including motorcycles, are increasingly using Light Emitting Diode (LED) lamps in the place of incandescent light bulbs in exterior lighting applications, including brake lamps, turn signals and parking lamps. Analysis of incandescent bulb filaments has been well documented (References 2, 3, 4, 5, 6 and 7), and is a well-accepted practice in accident analysis. But little appears to be known about how, or even if, LED lamps respond to the forces of acceleration or direct-impact events to provide a “record” of the state of the lamp at the moment of an accident event. This project examined the responses of lighted and unlighted LEDs to both acceleration and direct impact events for indications of their state of operation when damaged.

In an effort to improve the trade-off between fuel economy and emissions in the rotary combustion engine, research was undertaken to provide a better understanding of the sources of unburned hydrocarbons in the exhaust. Flame photography was used in conjunction with extensive time-resolved exhaust gas sampling. Examinations were made of the effects of air-fuel ratio, engine load, residual gas, and engine speed on combustion and hydrocarbon emissions using the two experimental techniques. These studies identified two major sources of hydrocarbon emissions: flame extinction and, not surprisingly, apex seal leakage. Conclusions were the following: (1) at lean air-fuel ratios (i.e., ≥18.0 to 1), flame extinction in the trailing portion of the chamber was a major source of exhaust hydrocarbons, and (2) at richer air-fuel ratios (i.e., ≤16.5 to 1), apex seal leakage was a major source of exhaust hydrocarbons.

The conventional ignition system utilizing an induction coil produces a spark consisting of a capacitive or high energy rate component and an inductive or low energy rate component. Predominant among conflicting arguments reported in the literature is the argument that the high energy rate component is the more effective for ignition of combustible mixtures. An investigation was conducted to measure the effect of the rate of energy release upon minimum spark ignition energy with electrode spacings greater than the quench distances reported in the literature. Lean, quiescent, propane-air mixtures were studied in a constant volume bomb. Results indicate that the minimum ignition energy decreased as the instantaneous peak power or peak rate of energy release was increased.