Sport Utility Vehicle

magine a place and time when, unless you lived in the Ozarks, you had not heard of Wal-Mart; when people drove station wagons, not sport utility vehicles; when the lament ''win- dows crashed'' meant kids were playing baseball in the empty lots outside; a time when using a computer meant lugging stacks or boxes of cards with little holes strategically

Untripped SUV (Sport Utility Vehicle) rollovers are dangerous and possibly lethal accidents. This thesis address some issues in the detection and prevention of untripped SUV rollovers. Before a rollover can occur, the wheels on one side must lose road contact. The wheel lift off situation is chosen as the critical situation to be avoided. If wheel lift off is prevented, then rollover is prevented as well. A new kinetic energy based measure, that indicates an imminent wheel lift off, is introduced. This measure is used by a gain scheduled LQ (Linear Quadratic) controller to prevent wheel lift off. The LQ controller outputs the desired changes of the forces acting on the chassis. These force changes are mapped to braking and traction system commands by a control allocator. Three different control alloca tion approaches were evaluated, including a new convex optimization approach. The convex optimization approach seems to work well. The controller is capable of preventing wheel lift off in the simulated test cases, and the results are promising.

High-sided, lightly loaded vehicles are known to be prone to accidents in strong, gusty winds. While wind related accidents may occur anywhere on roads, vehicles are more sensitive to wind while passing over bridges given the higher road elevations, exposure and possible speed-up effects at various bridge locations compared to ground level roads. The paper presents an extended roll-over model for estimation of vehicle stability in strong, gusty winds. The study example is of a Double-Deck Suspension Bridge where four typical vehicles were investigated, including: a tractor-trailer truck; an intercity bus; a courier van; and a full-sized SUV. Using a sectional model of the bridge deck and vehicle models built in scale, six component force and moment coefficients were measured at various lanes for the full azimuth of wind directions. The effects of the road level were also investigated. Based on expected wind turbulence properties at the bridge site and measurements of wind flow modifications at various deck locations, vehicle stability against roll-over has been predicted for various wind and vehicle speeds. For calibration purposes comparative tests and analyses on the same vehicles were carried out for the Confederation Bridge, PEI, Canada, and the results compared with the adopted policy for traffic control in strong winds on that bridge. Recommendations for traffic management in strong winds on tested bridges were drawn.

High-sided, lightly loaded vehicles are known to be prone to accidents in strong, gusty winds. While wind related accidents may occur anywhere on roads, vehicles are more sensitive to wind while passing over bridges given the higher road elevations, exposure and possible speed-up effects at various bridge locations compared to ground level roads. The paper presents an extended roll-over model for estimation of vehicle stability in strong, gusty winds. The study example is of a Double-Deck Suspension Bridge where four typical vehicles were investigated, including: a tractor-trailer truck; an intercity bus; a courier van; and a full-sized SUV. Using a sectional model of the bridge deck and vehicle models built in scale, six component force and moment coefficients were measured at various lanes for the full azimuth of wind directions. The effects of the road level were also investigated. Based on expected wind turbulence properties at the bridge site and measurements of wind flow modifications at various deck locations, vehicle stability against roll-over has been predicted for various wind and vehicle speeds. For calibration purposes comparative tests and analyses on the same vehicles were carried out for the Confederation Bridge, PEI, Canada, and the results compared with the adopted policy for traffic control in strong winds on that bridge. Recommendations for traffic management in strong winds on tested bridges were drawn.

There has been some discussion in the literature on the generation of ultrafine particles from tire abrasion of studded and non-studded tires tested in the laboratory environment. In the present study, the potential generation of ultrafine particles from the tire road interface was investigated during real driving. An instrumented Sport Utility Vehicle equipped with summer tires was used to measure particle concentrations with high temporal resolution inside the wheel housing while driving on a regular asphalt road. Different driving conditions, i.e., straight driving, acceleration, braking, and cornering were applied. For normal driving conditions no enhanced particle number concentration in the size range 6e562 nm was found. Unusual maneuvers associated with significant tire slip resulted in measurable particle concentrations. The maximum of the size distribution was between 30 and 60 nm. An exponential increase of the particle concentration with velocity was measured directly at the disc brakes for full stop brakings. A tracer gas experiment was carried out to estimate the upper limit of the emission factor during normal straight driving.

TURTLE is a real-time UML profile supported by a toolkit which enables application of formal verification techniques to the analysis, design and deployment phases of systems design trajectory. This paper extends the TURTLE methodology with a requirement capture phase. SysML requirement diagrams are introduced. Temporal requirements (TR) are formally expressed using a dedicated language based on Allen's interval algebra. TRs serve as starting point to automatically synthesize observers and to guide the verification process applied to the TURTLE model of the system. Verification results are automatically collected in traceability matrices. A Hybrid Sport Utility Vehicle serves as example.

The paper presents the results of a study to define the wind speed limits and conditions beyond which fire and rescue vehicles should not be operated during a hurricane. For that purpose, reduced scale models of a typical fire truck, ambulance, and sports utility vehicle (SUV) were tested in a wind tunnel and surface pressures and overall forces were measured. For the fire truck wind tunnel tests, the pressure measurements at low yaw angles are compared with full-scale measurements on a real truck and the results are also compared to those from some numerical simulation, and give some confidence in the wind tunnel tests technique. Based on the results of the tests and the analyses, safe wind speeds are defined for the operation of these fire and rescue vehicles to prevent course deviation and overturning.

This paper proposes a methodology and approach to understand battery performance and life through driving cycle and duty cycle analyses from electric and hybrid vehicle (EHV) operation in real-world situations. Conducting driving cycle analysis with trip data collected from EHV operation in real life is very difficult and challenging. In fact, no comprehensive approach has been accepted to date, except those using standard driving cycles on a dynamometer or a track. Similarly, analyzing duty cycle performance of a battery under real-life operation faces the same challenge. A successful driving cycle analysis, however, can significantly enhance our understanding of EHV performance in real-life driving. Likewise, we also expect similar results through duty cycle analysis for batteries. Since 1995, we have been developing tools to analyze EHV and power source performance. In particular, we were able to collect data from a fleet of 15 Hyundai Santa Fe electric sports utility vehicles (e-SUVs) operated on Oahu, Hawaii; from July 2001 to June 2003 to allow driving and duty cycle analyses in order to understand battery pack performance from a variety of EHV operating conditions. We thus developed a comprehensive approach that comprises fuzzy logic pattern recognition (FL-PR) techniques to perform driving and duty cycle analyses. This approach has been successfully applied to EHV performance analysis via the creation of a compositional driving profile called "driving cycle profile" (DrCP) for each trip. The same approach was used to analyze battery performance via the construction of "duty cycle profile" (DuCP) to express battery usage under various operating conditions. The combination of the two analyses enables us to understand both the usage profile of EHV and battery performance in synergetic details and in a systematic manner using a pattern recognition technique.

The energy consumption of animal- and plant-based diets and, more broadly, the range of energetic planetary footprints spanned by reasonable dietary choices are compared. It is demonstrated that the greenhouse gas emissions of various diets vary by as much as the difference between owning an average sedan versus a sport-utility vehicle under typical driving conditions. The authors conclude with a brief review of the safety of plant-based diets, and find no reasons for concern.

In this paper we present a methodology based on multiple models and switching for realtime estimation of center of gravity (CG) position in automotive vehicles. The method utilizes well-known simple linear vehicle models for lateral and roll dynamics and assumes the availability of standard stock automotive sensors. We illustrate the technique with numerical simulations as well as with measured sensor data from an SUV vehicle. We also compare our estimation results with traditional linear-least squares estimators to show the efficacy of our technique. Finally, we give a simple application example for implementing the idea in automotive vehicles as a switch for rollover controller activation.

Real-time knowledge of the slip angle in a vehicle is useful in many active vehicle safety applications, including yaw stability control, rollover prevention, and lane departure avoidance. Sensors to measure slip angle, including two-antenna GPS systems and optical sensors, are too expensive for ordinary automotive applications. This paper develops a real-time algorithm for estimation of slip angle using inexpensive sensors normally available for yaw stability control applications. The algorithm utilizes a combination of model-based estimation and kinematics-based estimation. Compared with previously published results on slip angle estimation, this present paper compensates for the presence of road bank angle and variations in tire-road characteristics. The developed algorithm is evaluated through experimental tests on a Volvo XC90 sport utility vehicle. Detailed experimental results show that the developed system can reliably estimate slip angle for a variety of test maneuvers.

Now that the U.S. Environmental Protection Agency has promulgated new National Ambient Air Quality Standards for PM 2.5 , work will begin on generating the data required to determine the sources of ambient PM 2.5 and the magnitude of their contributions to air pollution. This paper summarizes the results of an Environmental Research Consortium program, carried out under the auspices of the U.S. Council for Automotive Research. The program focused on particulate matter (PM) emissions from representative, current-technology, light-duty gasoline vehicles produced by DaimlerChrysler Corp., Ford Motor Co., and General Motors Corp. The vehicles, for the most part taken from the manufacturer's certification and durability fleets, were dynamometer-tested using the three-phase Federal Test Procedure in the companies' laboratories. The test fleet was made up of a mixture of both lowmileage (2K-35K miles) and high-mileage (60K-150K miles) cars, vans, sport utility vehicles, and light trucks. For each vehicle tested, PM emissions were accumulated over 4 coldstart tests, which were run on successive days. PM emission rates from the entire fleet (22 vehicles total) averaged less than 2 mg/mile. All 18 vehicles tested using California Phase 2 reformulated gasoline had PM emission rates less than 2 mg/ mile at both low and high mileages. IMPLICATIONS Motor vehicles are a source of PM. The significance of vehicles as contributors to urban environmental particle concentrations needs to be evaluated from both environmental and vehicle measurement data. This report provides particle emissions data for current-technology (1994-1998) gasoline vehicles at both low and high mileages. Particle emission rates for both low-and highmileage vehicles, using California reformulated fuel, are about 2 mg/mile.

Untripped SUV (Sport Utility Vehicle) rollovers are dangerous and possibly lethal accidents. This thesis address some issues in the detection and prevention of untripped SUV rollovers. Before a rollover can occur, the wheels on one side must lose road contact. The wheel lift off situation is chosen as the critical situation to be avoided. If wheel lift off is prevented, then rollover is prevented as well. A new kinetic energy based measure, that indicates an imminent wheel lift off, is introduced. This measure is used by a gain scheduled LQ (Linear Quadratic) controller to prevent wheel lift off. The LQ controller outputs the desired changes of the forces acting on the chassis. These force changes are mapped to braking and traction system commands by a control allocator. Three different control alloca tion approaches were evaluated, including a new convex optimization approach. The convex optimization approach seems to work well. The controller is capable of preventing wheel lift off in the simulated test cases, and the results are promising.

The plug-in hybrid electric vehicle (PHEV), utilizing more battery power, is considered a next-generation hybrid electric vehicles with great promise of higher fuel economy. The charge-depletion mode is more appropriate for the power management of PHEV, i.e. the state of charge (SOC) is expected to drop to a low threshold when the vehicle reaches the destination of the trip. Global optimization charge-depletion power management would be desirable. However, this has so far been hampered due the a priori nature of the trip information and the almost prohibitive computational cost of global optimization techniques such as dynamic programming (DP). This situation can be changed by the current advancement of Intelligent Transportation Systems (ITS) based on the use of on-board GPS, GIS, real-time and historical traffic flow data and advanced traffic flow modeling techniques. In this paper, gas-kinetic base trip modeling approach was used for the highway portion trip and for the local road portion the traffic light sequences throughout the trip will be synchronized with the vehicle operation. Several trip models approaches were studied for a specific case. The simulation results demonstrated significant improvement in fuel economy using DP based charge-depletion control compared to rule based control. The gas-kinetic based trip model for the highway portion can describe the dynamics of the traffic flow on highway with on/off ramps which may be missed by the model which used only the main road detectors data.

The aims of this study are to investigate the responses of a Hybrid III dummy and a human body model in rollover crashes of an SUV, and to assess the effect of an inflatable tubular structure (ITS) on the unrestrained occupant kinematics in rollover events. A SAEJ2114 rollover test of a 1994 Ford Explorer with an inflatable tubular structure (ITS) is simulated for two front row occupants, and validated in MADYMO. By removing the ITS, the simulation of the Hybrid III dummy occupants without ITS is obtained. By replacing the dummy models with human body models, with and without ITS, two other simulations are also modelled. The kinematics and injury risks of the two occupant models are compared and evaluated. Significant differences exist in the motions, and injury levels of the dummies and human body models with and without ITS. ITS can offer significant protection to the head by cushioning the impact of the head on the roof or side windows, and can mitigate against occupant ejection. The flexibility of the spine and the neck of the human body models significantly affects the kinematics and the severity of the injuries of the occupants modelled, and so would also affect the relevance of the design of countermeasures developed from dummy tests to real-world rollover crashes of human beings.

Successful new product introduction requires that product characteristics relate to the customer on functional, emotional, aesthetic and cultural levels. As part of research into automotive Human Machine Interfaces (HMI), this paper describes holistic customer research carried out to investigate how the haptics of switches in luxury Sports Utility Vehicles (SUVs) are perceived by customers. The application of these techniques, including an initial proposal for objective specifications, is addressed within the broader New Product Introduction context, and benefits described. 101 customers of SUVs assessed the feel of automotive push switches, completing the tasks both in, and out of vehicles to investigate the effect of context. Using the semantic differential technique, hedonic testing, and content analysis of customers' verbatim comments, a holistic picture has been built up of what influences the haptic experience. It was found that customers were able to partially discriminate differences in switch-feel, alongside considerations of visual appearance, image, and usability. Three factors named 'Affective', 'Robustness and Precision', and 'Silkiness' explained 61% of the variance in a principle components analysis. Correlations of the factors with acceptance scores were 0.505, 0.371, and 0.168 respectively.

We present a general approach for multi-modal sensor fusion based on nonparametric probability density estimation and maximization of a mutual information criterion. We apply this approach to fusion of vector-magnetic and acoustic data for classification of vehicles. Linear features are used, although the approach may be applied more generally with other sensor modalities, nonlinear features, and other classification targets. For the magnetic data, we present a parametric model with computationally efficient parameter estimation. Experimental results are provided illustrating the effectiveness of a classifier that discriminates between cars and sport utility vehicles.

one year, rollover impacts accounted for 9 percent of multiple-vehicle accident fatalities while rollovers accounted for 51 percent of single-vehicle accident fatalities. Light-duty vehicles include passenger cars, pickup trucks, vans, and sport-utility vehicles. Although much attention has been given to the study of vehicle rollover stability and to rollover-accident avoidance, research has yet to conclusively uncover an individual vehicle characteristic

Many investigators have predicted that the performance gains attainable with a semiactive suspension are comparable with those possible with a fully active suspension. To achieve this, one of the crucial factors is the method by which the damper is controlled. This study is an investigation, through simulation, into the effectiveness of a number of basic control strategies in controlling vehicle dynamics, particularly roll. In addition, this study examines the effect of changing the vehicle mass on the effectiveness of selected semiactive control policies. The model represents a sport utility vehicle (SUV), a class of vehicles that regularly sees widely varying vehicle weight and exhibits undesirable levels of vehicle roll. In this study, a four-degree-of-freedom vehicle roll plane model is subjected to a variety of road- and driver-induced inputs, and the vehicle response with different semiactive control policies is characterized. The semiactive control policies investigated are t...

Rising oil prices and concerns about energy security and climate change are spurring reconsideration of both automobile propulsion systems and the fuels that supply energy to them. In addition to the gasoline internal combustion engine, recent years have seen alternatives develop in the automotive marketplace. Currently, hybrid-electric vehicles, advanced diesels, and flex-fuel vehicles running on a high percentage mixture of ethanol and gasoline (E85) are appearing at auto shows and in driveways. We conduct a rigorous benefit-cost analysis from both the private and societal perspective of the marginal benefits and costs of each technology-using the conventional gasoline engine as a baseline. The private perspective considers only those factors that influence the decisions of individual consumers, while the societal perspective accounts for environmental, energy, and congestion externalities as well. Our analysis illustrates that both hybrids and diesels show promise for particular light-duty applications (sport utility vehicles and pickup trucks), but that vehicles running continuously on E85 consistently have greater costs than benefits. The results for diesels were particularly robust over a wide range of sensitivity analyses. The results from the societal analysis are qualitatively similar to the private analysis, demonstrating that the most relevant factors to the benefit-cost calculations are the factors that drive the individual consumer's decision. We conclude with a brief discussion of marketplace and public policy trends that will both illustrate and influence the relative adoption of these alternative technologies in the United States in the coming decade.

Cycling is widely viewed as a transport mode with marginal environmental impacts. However, such a view fails to take account of such factors as the increase in carbon dioxide exhaled as a result of increased physical activity or the emission embodied in the manufacture of the bicycle. This paper presents estimates of emission factors for various forms of commuter transport in Ireland that allow comparison against emissions from cycling. When indirect energy is taken into account, the results presented here indicate that a cyclist commuting an equivalent distance to work releases an almost equal amount of carbon dioxide as that attributed to a passenger of an electrically propelled train at full occupancy during peak service times. Travel by bicycle is much less carbon intensive when compared to passengers travelling at off-peak times. Transport by car and sports utility vehicle is the most carbon intensive of the commuter modes of transport studied, however, travelling in a fully occupied car has an emission factor approaching that of off-peak bus transport.

With funding from the U.S. Department of Energy’s Vehicle Technologies Office, the National Renewable Energy Laboratory (NREL) conducts real-world performance evaluations of advanced medium- and heavy-duty fleet vehicles. Evaluation results can help vehicle manufacturers fine-tune their designs and assist fleet managers in selecting fuel-efficient, low-emission vehicles that meet their economic and operational goals. In 2011, NREL launched a large-scale performance evaluation of medium-duty electric vehicles. With support from vehicle manufacturers Smith and Navistar, NREL research focused on characterizing vehicle operation and drive cycles for electric delivery vehicles operating in commercial service across the nation.

Aerodynamic styling of the vehicle is one of the promising technologies which can not only improve the fuel efficiency, but also ensure better stability and good handling characteristics of vehicles at higher speed especially on highways. The paper includes assessment of drag force (F d) and drag coefficient (C d) by the conventional wind tunnel method. The experimental calculations were performed using subsonic wind tunnel having a test section of 100cm x 30cm x 30 cm. An exact replica of a model of Sports Utility Vehicle (SUV) on reduced scale 1:32 was used to conduct and perform the experiment for calculating F d and C d. Threedimensional (3D) computational analysis was carried out using Gambit as the preprocessing software and Fluent as the solver and post-processor. The comparison of computational approaches with experiment shows that the computed F d agrees well with the experimental values over the entire range of air velocities.

While climbing a properly set up aluminum extension ladder, a workman fell with the ladder after a crack completely penetrated one of the side rails. The crack initiated at a site which corresponded exactly with the location where the side rail normally rests on a steel ladder rack during transport. There are a number of recommended countermeasures in the ANSI ladder standards for preventing ladder damage from road shock and vehicle vibration including one which suggests securing the ladder at each support point. This bulletin demonstrates that the latter recommendation alone will prevent fretting damage and its associated loss of structural integrity.

Two types of ambulances and a city bus were modeled in a wind tunnel for the minimum wind speed required to upset the stationary vehicles. The Type I ambulance was vulnerable to upset with wind speeds of 135 to 150 mph on the vehicle over wind angles of 40° to 145°. The Type II ambulance was vulnerable to upset with wind speeds of 140 to 170 mph over wind angles of 30° to 145°. The 40-passenger city bus was vulnerable to upset with wind speeds of 60 to 75 mph over wind angles of 35° to 145°. These results showed ambulances were more stable in high winds than common passenger vehicles, but the city bus was very vulnerable in high winds. Testing showed that moving ambulances can be driven at low speeds in minimal hurricane-force winds without exceeding the upset wind speeds on the vehicles. This information provides guidance for safe operation of these vehicles during high winds including hurricanes, thunderstorms, and extra-tropical cyclones.

Car-Pedestrian accidents cause a loss of thousands of lives annually in addition to injuries. Therefore, pedestrian protection is one of the important issue in the design of friendly cars. This study shows the performance of finite element head model (FEM) to study and foretelling the extent of injury that occurs at pedestrian accidents and tests the design of the front of vehicle according to European Enhanced Vehicle-Safety Committee (EEVC WG17) regulations of bonnet test. The FE models are powerful tools and effective method to understand how to reduce the sever ity of the fatalities of injuries in road pedestrian collision incidents. In this study, the finite element head model impactor has been built by using Soldworks program and simulated the impact process in LS-DYNA program to examine the four engine-hoods have been designed. All of the hood plates and inner hood panel were considered. Head Injury Criterion (HIC), internal energy time history generated in the head and hood, displacement occurred in the hood i nner panel and weights of the complete hood are investigated. The results of the study concluded that modification of headform des ign of the car hood contributes in achieving low HIC and lead to a pedestrian friendly car. The results show that the structural design of the inner hood panel is one of the key factors affecting the design and specifications of car hood.

A cyclical conditional maximum likelihood estimation procedure is developed for the multidimensional unfolding of two-or three-way dominance data (e.g., preference, choice, consideration) measured on ordered successive category rating scales. The technical description of the proposed model and estimation procedure are discussed, as well as the rather unique joint spaces derived. We then conduct a modest Monte Carlo simulation to demonstrate the parameter recovery of the proposed methodology, as well as investigate the performance of various information heuristics for dimension selection. A consumer psychology application is provided where the spatial results of the proposed model are compared to solutions derived from various traditional multidimensional unfolding procedures. This application deals with consumers intending to buy new luxury sport-utility vehicles (SUVs). Finally, directions for future research are discussed.

Here we report the analysis of vehicle usage of a fleet of 15 Hyundai Santa Fe electric-sport-utility-vehicles (e-SUVs), which was tested in Honolulu, Hawaii, from July 2001 to June 2003. The 15 vehicles were dispatched to the Hickam Air Force Base (HAFB), City and County (C&C) of Honolulu, Hawaiian Electric Co. (HECO), and the Hawaii Electric Vehicle Demonstration Project (HEVDP) office for field evaluation. More than 25,000 trips were recorded using on-board data acquisition systems in all vehicles during the two-year period, representing a total driving distance of more than 255,000 km. We used a systematic approach to conduct driving cycle analysis (DCA) from the second-by-second trip data. Detailed breakdown of the driving cycles in terms of driving patterns was generated and summarized as functions of vehicle operating time and mileage for each vehicle over the evaluation period. In this paper, we illustrate how to analyze the vehicle usage from such a DCA and the real-life data in the database. The vehicle usage analysis (VUA) includes frequency and extent of vehicle operation in addition to the DCA. We intend to correlate vehicle performance via DCA and VUA for comparison among different operating organizations to allow us develop a more effective fleet operation in the future.

The development of a new concept of wind alarm systems for road and rail transportation is presented. The alarm is funded on a risk assessment approach, taking into account wind modelling and prediction, aerodynamic forces, vehicle dynamics.

To determine why road deaths dropped by 33.9% in the United Kingdom, compared to 6.5% in the United States, between 1990 and 1999. Methods: Deaths per billion vehicle kilometers traveled (D/BVKM), and case fatality rates (CFR) in the United States and the United Kingdom were tracked. Time trends in CFR can be used to track the direct effects of speed of impact. CFR is a crash-phase outcome that is independent of exposure, and varies approximately to the fourth power of the speed of crash impact. Joinpoint regression analysis was used to analyze changes in time trends of CFR. Results: In the 1990s, the decrease in deaths in the United Kingdom was attributable mostly to the 29.6% drop in the CFR. In the United States, the CFR dropped by only 6.6%. The United Kingdom introduced speed cameras and an array of speed-calming measures. By contrast, in the United States, use of speed cameras was extremely rare, and speed limits and speeds increased in 32 of the 50 states, mostly in 1995 and 1996, after which CFR actually rose (p Ͻ.0001). Intercountry differences in time trends in seat belt use, trauma care, vehicle kilometers traveled, congestion, and driving under the influence of alcohol (DUI), along with massive increase in use of higher-risk sports utility vehicles in the United States, did not account for the contrasting trends in deaths through the 1990s. But increases in DUI in the United States after 1997 may have contributed to increases in speed-related crashes. Conclusions: The reductions in CFR, probably from small drops in speed of impact account for the disproportionately greater drop in death tolls in the United Kingdom compared to the United States. The temporal fit between drops in CFR and deaths following the introduction of speed cameras in the United Kingdom and increases in speed (speed creep), CFR, and deaths in the United States following raised speed limits suggests that diverging changes in speeds of impact accounted mainly for these changes. Use of D/BVKM to correct for exposure concealed the lack of progress after 1990 in the United States, since falling time trends in D/BVKM reflect increases in congestion. If the United States had implemented United Kingdom-type speed control policies and not raised speed limits, there would have been an estimated 6500 to 10,000 (ϳ16% to 25%) fewer road deaths per year during the period following speed-limit increases (1996 to 1999), including many DUI-related deaths. Reductions of up to 50% are now achievable based on newer population-wide strategies for speed control.

To determine why road deaths dropped by 33.9% in the United Kingdom, compared to 6.5% in the United States, between 1990 and 1999. Methods: Deaths per billion vehicle kilometers traveled (D/BVKM), and case fatality rates (CFR) in the United States and the United Kingdom were tracked. Time trends in CFR can be used to track the direct effects of speed of impact. CFR is a crash-phase outcome that is independent of exposure, and varies approximately to the fourth power of the speed of crash impact. Joinpoint regression analysis was used to analyze changes in time trends of CFR. Results: In the 1990s, the decrease in deaths in the United Kingdom was attributable mostly to the 29.6% drop in the CFR. In the United States, the CFR dropped by only 6.6%. The United Kingdom introduced speed cameras and an array of speed-calming measures. By contrast, in the United States, use of speed cameras was extremely rare, and speed limits and speeds increased in 32 of the 50 states, mostly in 1995 and 1996, after which CFR actually rose (p Ͻ.0001). Intercountry differences in time trends in seat belt use, trauma care, vehicle kilometers traveled, congestion, and driving under the influence of alcohol (DUI), along with massive increase in use of higher-risk sports utility vehicles in the United States, did not account for the contrasting trends in deaths through the 1990s. But increases in DUI in the United States after 1997 may have contributed to increases in speed-related crashes. Conclusions: The reductions in CFR, probably from small drops in speed of impact account for the disproportionately greater drop in death tolls in the United Kingdom compared to the United States. The temporal fit between drops in CFR and deaths following the introduction of speed cameras in the United Kingdom and increases in speed (speed creep), CFR, and deaths in the United States following raised speed limits suggests that diverging changes in speeds of impact accounted mainly for these changes. Use of D/BVKM to correct for exposure concealed the lack of progress after 1990 in the United States, since falling time trends in D/BVKM reflect increases in congestion. If the United States had implemented United Kingdom-type speed control policies and not raised speed limits, there would have been an estimated 6500 to 10,000 (ϳ16% to 25%) fewer road deaths per year during the period following speed-limit increases (1996 to 1999), including many DUI-related deaths. Reductions of up to 50% are now achievable based on newer population-wide strategies for speed control.

Previous work examined degree of hybridization on the fuel economy of a hybrid electric sport utility vehicle. It was observed that not only was the vehicle control strategy important, but that its definition should be coupled with the component sizing process. Both degree of hybridization and the energy management strategy have been optimized simultaneously in this study. Simple mass scaling algorithms were employed to capture the effect of component and vehicle mass variations as a function of degree of hybridization. Additionally, the benefits of regenerative braking and power buffering have been maximized using optimization methods to determine appropriate battery pack sizing. Both local and global optimization routines were applied to improve the confidence in the solution being close to the true optimum. An optimal configuration and energy management strategy that maximizes the benefit of hybridization for a hydrogen fuel cell hybrid SUV was derived. The optimal configuration ...

Although the rapid growth in light truck vehicle (LTV) sales, including minivans, sports utility vehicles (SUVs), and light-duty trucks, has not been associated with an overall increase in collisions or traffic deaths in the US, there is a need for a research program to determine whether particular types of collisions have become more frequent or injurious because of the increase in the percent of LTVs in traffic. This paper presents an analysis of the effect of the increasing number of LTV registrations on fatal angle collision trends in the US. The analysis investigates the number of annual fatalities that result from angle collisions as well as collision configuration (car-car, car-LTV, LTV-car, and LTV-LTV). The analysis uses the Fatality Analysis Reporting System (FARS) crash databases covering the period 1975-2000. Results showed that death rates differ based on the collision configuration. Time series modeling results showed that fatalities in angle collisions will increase in the next 10 years, and that they are affected by the expected increase in the percentage of LTVs in traffic. Forecast showed that the total number of annual deaths is expected to reach 6300 deaths by the year 2010 (an increase of 12% over 2000). Analysis into the configuration of the collision indicated the seriousness of angle collisions involving an LTV striking a common passenger car (LTV-car). A time series model illustrated the significance of time lag and percent of LTVs in traffic on the increase of this type of fatal collisions. Forecasts from the time series model indicated a 32% increase in deaths due to this type of collisions in the next 10 years.

We examine older Americans' choice of vehicle types and the impact of age and health status on this choice. Using the 1998 and 2000 Health and Retirement Study (HRS) and the 2001 HRS Consumption and Activities Mail Survey (CAMS), we estimate a multinomial logit model of older Americans' choice of vehicle types. We find that both age and health status influence the type of vehicle purchased or leased. Compared to Americans aged 50-59, those aged 70 or older prefer passenger cars to trucks and sport utility vehicles (SUVs). We also find that elders with health problems are more likely to prefer SUVs to passenger cars than those without health problems.

Previous studies have identified a fatality risk for children exposed to air bags, particularly in the presence of non-restraint or inadequate restraint of the child and pre-impact braking, conditions that place the child out-of-position. Consequently, many manufacturers are opting to suppress the air bag when an out-of-position child, particularly one who is unrestrained, is detected. This study provides current estimates of injury risk for children exposed to airbags based on the large experience of children in crashes from the Partners for Child Passenger Safety (PCPS) project; describes the most common scenarios for these injuries; and attempts to replicate and extend the field data through sled testing and simulations. This study was conducted to enhance the scientific base on which decisions to suppress airbags can be made on restrained children. The results of this study suggest that more investigation must be conducted before air bag suppression for restrained children is chosen as the option for future air bags. Surveillance data suggest that restrained children are not at as high a fatality risk as previously reported for predominantly unrestrained children and that injuries that restrained children exposed to airbags receive are mostly not life-threatening. However, the performance of air bags for children varies widely among vehicle types. Of particular concern are sport utility vehicles (SUV) and passenger vans: children in the front seat of these vehicles and not exposed to an air bag were at a very low risk of injury but children in similar severity crashes in these vehicles who were exposed to airbags were at a considerable increased risk of injury. In addition, consideration should be given to the evaluation of the risk of upper extremity fractures, as this is one of the most common injuries for children exposed to airbags. Dynamic sled tests (29kph pulse) were conducted in both a mid-sized car and sport utility vehicle buck. Results were extended using validated MADYMO models. Both sled testing and simulation results suggest a possible beneficial role of the air bag for certain crash scenarios involving children. Implications of the data for current child dummy design and airbag suppression considerations will be discussed.

In this paper, the methodology capable of computing a Time-To-Rollover (TT'R) index in real-time [1] is verified by using test data of two Sports-Utility Vehicles (S W)-a 1988 Suzuki Samurai and a 1997 Jeep Cherokee. First, simple yaw-roll models are constructed based on the test data. The TTR is computed from the simple model and then corrected by using an Artificial Neural Network. The TT'R generated by the Neural Network is then verified against the data for the two test vehicles.

one year, rollover impacts accounted for 9 percent of multiple-vehicle accident fatalities while rollovers accounted for 51 percent of single-vehicle accident fatalities. Light-duty vehicles include passenger cars, pickup trucks, vans, and sport-utility vehicles. Although much attention has been given to the study of vehicle rollover stability and to rollover-accident avoidance, research has yet to conclusively uncover an individual vehicle characteristic

Although the rapid growth in light truck vehicle (LTV) sales, including minivans, sports utility vehicles (SUVs), and light-duty trucks, has not been associated with an overall increase in collisions or traffic deaths in the US, there is a need for a research program to determine whether particular types of collisions have become more frequent or injurious because of the increase in the percent of LTVs in traffic. This paper presents an analysis of the effect of the increasing number of LTV registrations on fatal angle collision trends in the US. The analysis investigates the number of annual fatalities that result from angle collisions as well as collision configuration (car-car, car-LTV, LTV-car, and LTV-LTV). The analysis uses the Fatality Analysis Reporting System (FARS) crash databases covering the period 1975-2000. Results showed that death rates differ based on the collision configuration. Time series modeling results showed that fatalities in angle collisions will increase in the next 10 years, and that they are affected by the expected increase in the percentage of LTVs in traffic. Forecast showed that the total number of annual deaths is expected to reach 6300 deaths by the year 2010 (an increase of 12% over 2000). Analysis into the configuration of the collision indicated the seriousness of angle collisions involving an LTV striking a common passenger car (LTV-car). A time series model illustrated the significance of time lag and percent of LTVs in traffic on the increase of this type of fatal collisions. Forecasts from the time series model indicated a 32% increase in deaths due to this type of collisions in the next 10 years.

Dynamometer testing in conjunction with high-resolution FTIR spectroscopy was used to measure exhaust emissions of nitrous oxide (N 2 O) from a fleet of 37 light-duty vehicles at the California Air Resources Board. Exhaust emissions were collected for two driving cycles: the Urban Dynamometer Driving Schedule and the Unified Cycle. The vehicles studied, including passenger cars, sport utility vehicles, and light-duty trucks, were a sub-sample of a fleet that represented California's in-use fleet. The highest correlation between the emissions of N 2 O and other vehicle-exhaust species was, as expected, between N 2 O and nitrogen oxides (r 2 ¼ 0:45). The previously reported impact of catalyst aging on N 2 O emissions could not be verified by our data. Type of catalyst, driving cycle, and vehicle were demonstrated to be the main factors determining the magnitude of N 2 O emissions from gasoline-powered light-duty vehicles. The average N 2 O emissions factor for the 37 vehicles tested was 2074 mg km À1 , with a factor of 50 difference between the lowest (2 mg km À1) and highest (100 mg km À1) N 2 O emissions. The average value for N 2 O/NO x emissions ratios was 0.09570.035, with a factor of 14 difference between the lowest (0.01) and the highest (0.14) ratios.

The variation of the throwing distance and Head Injury Criterion with car velocity, point of impact and angle of approach has been studied for bicycle impact with three different categories of vehiclessmall cars, sports utility vehicles and buses. Crashes between a bicycle and the vehicles were simulated using multi body models developed in MADYMO TM with parametric variations in speed, angle of approach and point of impact. The variation in the angle of approach or point of contact causes significant changes. From the simulations, the large spread in the data reported by reconstruction is predicted to originate from variation in the impact configuration. The changes in the trends can be associated with key changes in the nature of the impact visible in the simulations (head impacting car, no impact of rider with car etc.). The kinematics of impact has significant differences in case of the bus and this leads to differences in the nature of correlations. The HIC values were found to be higher in the case of bus as compared to the SUV and the small car. The paper reinforces the hypothesis that for bicycle accident reconstruction should take into account variations in the impact configuration in addition to the throw distance recorded. The paper also gives data which when populated further could form a basis of such reconstructions.

The variation of the throwing distance and Head Injury Criterion with car velocity, point of impact and angle of approach has been studied for bicycle impact with three different categories of vehiclessmall cars, sports utility vehicles and buses. Crashes between a bicycle and the vehicles were simulated using multi body models developed in MADYMO TM with parametric variations in speed, angle of approach and point of impact. The variation in the angle of approach or point of contact causes significant changes. From the simulations, the large spread in the data reported by reconstruction is predicted to originate from variation in the impact configuration. The changes in the trends can be associated with key changes in the nature of the impact visible in the simulations (head impacting car, no impact of rider with car etc.). The kinematics of impact has significant differences in case of the bus and this leads to differences in the nature of correlations. The HIC values were found to be higher in the case of bus as compared to the SUV and the small car. The paper reinforces the hypothesis that for bicycle accident reconstruction should take into account variations in the impact configuration in addition to the throw distance recorded. The paper also gives data which when populated further could form a basis of such reconstructions.

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We examine older Americans' choice of vehicle types and the impact of age and health status on this choice. Using the 1998 and 2000 Health and Retirement Study (HRS) and the 2001 HRS Consumption and Activities Mail Survey (CAMS), we estimate a multinomial logit model of older Americans' choice of vehicle types. We find that both age and health status influence the type of vehicle purchased or leased. Compared to Americans aged 50-59, those aged 70 or older prefer passenger cars to trucks and sport utility vehicles (SUVs). We also find that elders with health problems are more likely to prefer SUVs to passenger cars than those without health problems.