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Stevens S.,Volpe Center | Bellone J.,Volpe Center | Azeredo P.,Volpe Center | Medri M.,Volpe Center
SAE International Journal of Transportation Safety | Year: 2017

This study is aimed at supporting left-turn assist (LTA) applications, which provide warnings to drivers making a left turn across the path of oncoming traffic (LTAP/OD scenarios). The primary goal was to provide much-needed information on typical or "baseline" driving in LTAP/OD scenarios that can be used to refine alert criteria to reduce false and nuisance alerts. A secondary goal was to provide performance data useful for informing practical test procedures, e.g., setting turning speed when evaluating LTA applications on a test track. To accomplish this, LTAP/OD events were identified in the databases of two large-scale naturalistic driving studies. For these events, we estimated the size of the gaps in oncoming traffic into which drivers chose to turn, what factors (environmental, demographic, etc.) affected the choice to turn into a gap of a given size, and the speed profiles throughout each turn. The factors with the largest effect on gap size were age and gender, followed by road wetness, whether or not the turning vehicle stopped before turning, and the number of lanes the turning vehicle had to cross. As a counterpoint to this analysis of safe, typical turning behavior, we also identified instances in a national crash database where LTAP/OD maneuvers led to serious collisions involving vehicles equipped with event data recorders, i.e., scenarios where an alert could have been useful. Speed profiles for turning vehicles did not differ strongly for collisions as compared to baseline driving, but estimated gap sizes were shorter. © 2016 SAE International.


News Article | August 23, 2016
Site: www.greencarcongress.com

With funding from Bioenergy Technologies Office (BETO), Pacific Northwest National Laboratory (PNNL) has been working with industry-partner LanzaTech to convert alcohols derived from captured carbon monoxide, a byproduct in the production of steel, into synthetic paraffinic kerosene, a non-fossil-based jet fuel. The technology not only provides a viable source of sustainable jet fuel but also reduces the amount of greenhouse gasses emitted into the atmosphere. The team recently reached a significant milestone on the project, producing over five gallons of synthetic paraffinic kerosene in a lab environment. Five gallons is the quantity needed for “fit-for-purpose” testing. The accomplishment is part of the technology transfer process moving from bench top at PNNL to piloting at Freedom Pines, Georgia. With tight ASTM fuel specification requirements, both the demonstration of the process and the fit-for-purpose testing need to take place before the technology can be adopted commercially. The process works in two stages. First, LanzaTech captures waste carbon from refineries and manufacturing plants and feeds the CO-rich gas to microbes that consume the gas and produce ethanol. By itself, ethanol is unsuitable for jet engines because it contains oxygen and just doesn’t have the energy needed. After removing the oxygen, the resulting molecule, ethylene, is a gas and simply doesn’t have the properties to be used in modern turbofan engines. Consequently, during the second stage of the process, the ethanol is run through a PNNL-developed catalyst that converts ethanol to jet fuel by removing the oxygen and combining hydrocarbons, a process known as dehydration-oligomerization. However, ethanol dehydration-oligomerization technologies are typically difficult to control. To overcome the challenge, PNNL borrowed technology it developed to convert methanol to gasoline and created a new, specialized catalyst. The catalyst first removes water from the ethanol (dehydration), leaving behind ethylene. The small ethylene hydrocarbons are then combined (oligomerization) to form hydrocarbon chains large enough for jet fuel without forming aromatics that lead to sooting when burned. The fuel meets all the specifications required for use in commercial aviation—not an easy thing to do. Producing 5 gallons of jet fuel at PNNL’s Bioproducts, Sciences, and Engineering Laboratory demonstrates the catalyst is ready for the intermediate stage in testing. Researchers will now seek to produce 2,000 gallons of jet fuel. As PNNL successfully meets milestones, LanzaTech will scale up further. In 2011, PNNL, Lanzatech and Imperium jointly responded to a DOE call for proposals for a new aviation biofuel research project to convert biomass-derived alcohols to drop-in renewable jet fuel. Also in 2011, LanzaTech received a US$3-million contract from the United States Federal Aviation Administration (FAA), through the Department of Transportation’s John A. Volpe Center, to accelerate commercial availability of alcohol-to-jet (ATJ) renewable drop-in aviation fuel. (Earlier post.) Lanzatech has also been working with the UK’s largest bank, HSBC, and Virgin Atlantic on the development of the process that captures waste gases from industrial steel production and ferments them to ethanol, which is then chemically converted for use as jet fuel. (Earlier post.)


Sussmann T.R.,Volpe Center | Ruel M.,Canadian National Railway | Chrismer S.M.,Amtrak
Transportation Research Record | Year: 2012

Railway ballast is a critical element in the railway track support structure. The ballast is often overlooked when inspection tools are developed for track. When ballast is not functioning correctly, the strength of the track structure may be inadequate and thus compromise track stability. Track stability-related failures vary from rapid deterioration with little warning to slow and progressive deterioration with often predictable required maintenance. Ballast-related deterioration is progressive and usually provides visual evidence to warn maintenance personnel of needed rehabilitation. However, the blocked drainage that develops with fouled ballast can result in a saturated roadbed that is not stable and could rapidly deteriorate to an unsafe condition with little warning. Although massive failures are rare, if a side hill fill or embankment deteriorates to the point of becoming susceptible to massive failure, then the challenge becomes evaluation. More detailed knowledge of the track support condition will be needed for a thorough evaluation than can be provided by current track inspections, except for costly detailed visual inspections. The current standard of practice for ballast inspection and maintenance can be improved to reduce the risk of sudden failure. Much of the required technology, knowledge, and resources is already available and being utilized under the current system. A more precise evaluation of ballast condition is essential to identify thresholds related to unsafe track support conditions and to support effective maintenance plans.


Minnice P.,Volpe Center | Biernbaum L.,Volpe Center | Mortensen S.,Federal Transit Administration
21st World Congress on Intelligent Transport Systems, ITSWC 2014: Reinventing Transportation in Our Connected World | Year: 2014

As part of the U.S. Department of Transportation's ICM Initiative, Dallas Area Rapid Transit (DART) purchased new automatic passenger counter (APC) technology for their light rail system to provide passenger counts in real-time to their train control center and to provide data to the Integrated Corridor Management (ICM) decision support system. By gaining access to real-time passenger counts and location, DART hopes to respond more effectively to unplanned incidents on the rail network by enabling more responsive service adjustments such as bus bridging and additional consist deployment. This technology also allows DART to respond to mode shift recommendations that are part of the larger ICM project along the US-75 corridor. This paper summarizes how DART responded to rail incidents before the introduction of ICM, addresses what has changed after ICM deployment, and identifies constraints to optimum responses.


Badain N.,Southwest Research Institute | Reinhart T.,Southwest Research Institute | Cooper C.,Volpe Center | MacIsaac J.,National Highway Traffic Safety Admin. | Whitefoot J.,National Highway Traffic Safety Admin.
SAE International Journal of Commercial Vehicles | Year: 2015

This paper presents the fuel consumption results of engine and vehicle simulation modeling for a wide variety of individual technologies and technology packages applied to a long haul heavy duty vehicle. Based on the simulation modeling, up to 11% in fuel savings is possible using commercially available and emerging technologies applied to a 15L DD15 engine alone. The predicted fuel savings are up to 17% in a Kenworth T700 tractor-trailer unit equipped with a range of vehicle technologies, but using the baseline DD15 diesel engine. A combination of the most aggressive engine and vehicle technologies can provide savings of up to 29%, averaged over a range of drive cycles. Over 30% fuel savings were found with the most aggressive combination on a simulated long haul duty cycle. Note that not all of these technologies may prove to be cost-effective. The fuel savings benefits for individual technologies vary widely depending on the drive cycles and payload. Copyright © 2015 SAE International.


Cooper C.,Volpe Center | Reinhart T.,Southwest Research Institute | MacIsaac J.D.,National Highway Traffic Safety Admin. | Whitefoot J.,National Highway Traffic Safety Admin.
SAE International Journal of Commercial Vehicles | Year: 2015

This paper presents the results of engine and vehicle simulation modeling for a wide variety of individual technologies and technology packages applied to two medium-duty vocational vehicles. Simulation modeling was first conducted on one diesel and two gasoline medium-duty engines. Engine technologies were then applied to the baseline engines. The resulting fuel consumption maps were run over a range of vehicle duty cycles and payloads in the vehicle simulation model. Results were reported for both individual engine technologies and combinations or packages of technologies. Two vehicles, a Kenworth T270 box delivery truck and a Ford F-650 tow truck were evaluated. Once the baseline vehicle models were developed, vehicle technologies were added. As with the medium-duty engines, vehicle simulation results were reported for both individual technologies and for combinations. Vehicle technologies were evaluated only with the baseline 2019 diesel medium-duty engine. The vehicle technology combinations in the T270 delivery truck yielded from 1% to 12% fuel savings, averaged over all the duty cycles. Fuel savings for the diesel engine technology packages ranged from 1% to 5%, averaged over all the duty cycles. The simulation of gasoline engine technology packages produced from 6% to 9% and 6% to 10% for the V-6 and V-8 engines, respectively. The benefits of individual technologies vary widely depending on the drive cycles. Copyright © 2015 SAE International.


Reeves A.,Northeastern University | Grayhem R.,Northeastern University | Grayhem R.,Volpe Center
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2016

Rod-mediated 500 nm test spots were flashed in Maxwellian view at 5 deg eccentricity, both on steady 10.4 deg fields of intensities (I) from 0.00001 to 1.0 scotopic troland (sc td) and from 0.2 s to 1 s after extinguishing the field. On dim fields, thresholds of tiny (50) tests were proportional to √I (Rose-DeVries law), while thresholds after extinction fell within 0.6 s to the fully dark-adapted absolute threshold. Thresholds of large (1.3 deg) tests were proportional to I (Weber law) and extinction thresholds, to √I. Conclusions: rod thresholds are elevated by photon-driven noise from dim fields that disappears at field extinction; large spot thresholds are additionally elevated by neural light adaptation proportional to √I. At night, recovery from dimly lit fields is fast, not slow. © 2016 Optical Society of America.


Reinhart T.,Southwest Research Institute | Cooper C.,Volpe Center | Whitefoot J.,National Highway Traffic Safety Admin. | MacIsaac J.,National Highway Traffic Safety Admin.
SAE International Journal of Commercial Vehicles | Year: 2015

Medium- and Heavy Duty Truck fuel consumption and the resulting greenhouse gas (GHG) emissions are significant contributors to overall U.S. GHG emissions. Forecasts of medium- and heavy-duty vehicle activity and fuel use predict increased use of freight transport will result in greatly increased GHG emissions in the coming decades. As a result, the National Highway Traffic Administration (NHTSA) and the United States Environmental Protection Agency (EPA) finalized a regulation requiring reductions in medium and heavy truck fuel consumption and GHGs beginning in 2014. The agencies are now proposing new regulations that will extend into the next decade, requiring additional fuel consumption and GHG emissions reductions. To support the development of future regulations, a research project was sponsored by NHTSA to look at technologies that could be used for compliance with future regulations. Data presented in this paper detail how engine and vehicle simulation models were developed for current medium and heavy duty vehicles and then validated against available test results. In addition, the paper describes how potential future engine and vehicle technologies were added to the baseline models to simulate future improvements in medium and heavy duty vehicle fuel consumption and GHG emissions. Wherever possible, experimental data was used as inputs to the models or to validate the simulation results. The effect of drive cycle on engine efficiency is also explored. .


Pascal J.-P.,Montpellier University | Marquis B.,Volpe Center
Vehicle System Dynamics | Year: 2014

The Euler equation is a correct way for writing rotational moments of solids. But it is simple only if written in rotating frames. Applying it to railway wheelsets is difficult because it necessitates using the Euler angles, or Euler parameters, combined to rotation matrices or, numerically more stable, quaternions. Euler angles can be avoided in railway specific codes, by writing dynamical equations in track frames. However, academic literature [Landau LD, Lifshitz EM. Mechanics (Institute of Physical Problems, USSR Academy of Sciences, Moscow), Vol. 1, Course of theoretical physics. 21st English ed. Oxford (UK): Elsevier; 1960; Shabana AA, Zaazaa KE, Sugiyama H. Railroad vehicle dynamics. CRC Press; 2008.] does not provide simple solutions as to how properly writing equations of gyroscopic moments in no rotating frames. This paper describes how it is possible, owing to an approximation validated for railway applications, to avoid Euler angles and rotation matrices, while correctly taking into account gyroscopic effects. Using a most severe example, emphasising gyroscopic effects, it is demonstrated that a fast specific code using the approximation provides results equivalent to those of an multi body system generalised code with no approximation. © 2014 © 2014 Taylor & Francis.


De Cerchio R.,U.S. Federal Aviation Administration | Riley C.,Volpe Center
AIAA/IEEE Digital Avionics Systems Conference - Proceedings | Year: 2011

Aircraft manufacturers, avionics/electronics vendors, and owners/operators are implementing technologies (e.g. packet switching devices, wireless interfaces) that are easier to implement, reduce cost/size/weight/power, and increase connectivity but could potentially introduce cyber security vulnerabilities that affect aircraft safety. © 2011 IEEE.

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