Passenger Car Model Research Articles

The fit of competitive strategies and firm-specific advantages with country-specific advantages in explaining manufacturing location choices

PurposeThis paper aims to clarify the fit of competitive strategies and firm-specific advantages (FSAs) with country-specific advantages (CSAs) in explaining manufacturing location choices at product category level in the European automotive industry.Design/methodology/approachSeven hypotheses are formulated and tested using binomial logistic regression with data from 148 passenger car models (i.e. product category level) that are sold in Europe and manufactured in countries that offer CSAs of either cost advantages or differentiation advantages. The first four hypotheses test manufacturing location choices of product categories pursuing cost leadership strategy, differentiation strategy, focus strategy and hybrid strategy. The other three hypotheses test whether FSAs of R&D capability, marketing capability and operations capability will impact on the manufacturing location choice. The tests control for the type of passenger cars as well as the manufacturer’s region of origin.FindingsWhile pursuing cost leadership strategy leads to manufacturing in countries that offer cost advantages, pursuing differentiation strategy as well as strong R&D capability and marketing capability result in manufacturing in countries that offer differentiation advantages. Focus strategy, hybrid strategy and operations capability do not have an impact on the manufacturing location choice at product category level.Research limitations/implicationsConducting empirical research at product category level is subject to limitations in the choices of FSAs due to lack of availability of data.Practical implicationsManagers should assess the competitive strategies and FSAs of their product categories and then decide about manufacturing locations based on their fit with host country CSAs. Policymakers should understand the CSAs of their countries and target to attract manufacturing FDI from product categories with matching competitive strategies and FSAs.Originality/valueThe research contributes to discussions in explaining manufacturing location choices. Its originality lies in being the first study to test the fit of competitive strategies and FSAs of product categories with CSAs.

Case Study on Market Mix Strategies of Toyota Motor Corporation

Toyota Motor Corporation is a Japanese multinational automotive manufacturer headquartered in Toyota City, Aichi, Japan. In 2017, Toyota's corporate structure consisted of 364,445 employees worldwide and, as of September 2018, was the sixth-largest company in the world by revenue. As of 2017, Toyota is the world's second-largest automotive manufacturer. Toyota was the world's first automobile manufacturer to produce more than 10 million vehicles per year which it has done since 2012, when it also reported the production of its 200-millionth vehicle. As of July 2014, Toyota was the largest listed company in Japan by market capitalization and by revenue. Toyota is the world's market leader in sales of hybrid electric vehicles, and one of the largest companies to encourage the mass-market adoption of hybrid vehicles across the globe. Toyota is also a market leader in hydrogen fuel-cell vehicles. Cumulative global sales of Toyota and Lexus hybrid passenger car models achieved the 10 million milestones in January 2017. Its Prius family is the world's top selling hybrid nameplate with over 6 million units sold worldwide as of January 2017.

Cradle-to-gate greenhouse gas (GHG) burdens for aluminum and steel production and cradle-to-grave GHG benefits of vehicle lightweighting in China

Greenhouse gas (GHG) burdens of steel and aluminum production and life cycle benefits of vehicle lightweighting in China were evaluated. Production of advanced high-strength steel (AHSS) and wrought aluminum (Al) have average cradle-to-gate GHG emissions of 3.9 and 17.5 kg CO2eq/kg. Lightweighting benefits for eleven passenger car models over five driving cycles (including real-world and regulatory cycles) were determined. Lightweighting using AHSS to replace conventional steel has cradle-to-grave GHG savings in all cases, mainly attributed to savings in material use. Wrought Al has a much higher GHG production burden than AHSS and requires greater fuel savings in the use phase to achieve net cradle-to-grave GHG savings. Maximum GHG savings occur with Al versus AHSS in cases where the powertrain is resized, travel is congested, or lifetime travel distance is long. A typical Beijing peak-hour driving cycle with low speed and frequent stop-and-go has higher fuel reduction values (FRVs) and GHG savings than other cycles. Congested travel conditions make lightweighting a particularly effective emissions reduction strategy in China.

CFD studies for energy conservation in the HVAC system of a hatchback model passenger car

ABSTRACT Heating, Ventilation and Air Conditioning (HVAC) system of a passenger cabin in a vehicle is a largest auxiliary load in an automobile, apart from primary tractional load. A larger energy for HVAC system can reduce the driving range of an electric vehicle. The same condition may result in increase in fuel consumption of an engine-driven vehicle up to 25%. Excessive heating up of the passenger compartment is primarily caused by exposure of the vehicle to peak solar radiation. Energy conservation studies will reduce the energy consumption as well as initial size of cooling system. In the present work, the CFD analysis of a HVAC system in a hatchback car model has been carried out. The analysis was executed to find the baseload and temperature rise in an automobile passenger cabin without cooling. Following this, the cooling process has been implemented in the CFD model. Energy conservation measures, such as implementation of different types of insulation materials and window blinds have been carried out to study the temperature reduction by insulations and window blinds in the car cabin. The interior fluid domain of the car cabin has been modeled and simulated using ANSYS FLUENT 19.0 software. Results obtained from various simulations revealed the usefulness of the CFD simulation tool in studying the various parameters that are responsible for energy consumption in an automobile. The results taken from the simulation can be used by vehicle manufacturers for their vehicle advancement and they can develop a CFD model for optimizing the HVAC energy in an automobile.

Feasibility verification for anomaly detection of track structures based on vibration data form vehicle body

Strengthening the detection and monitoring of abnormal track structure is of great significance to ensure the good operation of high-speed trains. The feasibility of detecting abnormal track structure of lower structure based on vehicle body vibration acceleration is verified numerically in this paper. A passenger car model is firstly established by rigid body dynamics software SIMPACK, and the vibration response of the car body is obtained by adding the abnormal irregularity waveform of typical track on the track spectrum as the wheel-rail excitation. And then, by comparing the acceleration vibration response of different positions and directions on the car body, the optimal measuring point of vibration sensor on the car body is determined. The results show that the vertical vibration acceleration of the front and rear position of the car can effectively reflect the abnormality of the lower track structure. Using the vibration data of the car body as the medium can provide a new way for the rapid abnormal detection of the lower track structure.

Charging balance management technology for low-voltage battery in the car control unit with combined power system

The article presents the results of mathematical models and algorithms development complex, which is aimed at ensuring a positive charge balance of an automobile low-voltage rechargeable battery in car control systems with a hybrid power system. The aim of the work is to create and implement a set of software and mathematical models on one of the existing passenger car model, using the default components and systems of the car, to achieve a positive energy balance of the automotive low-voltage power network, and also to solve the problem of battery discharge by normalizing the turn-on time of powerful consumers leading to fast battery discharge. As criteria for the optimal performance of the proposed models and algorithms, the SOC parameters are considered - state of charge (%), battery charge (A * h), charge and discharge current of a battery (A), voltage on a battery during its charge when a charging current is absent or in a quiescent state (V), ambient temperature (˚C). Authors defined: composition of a control system, the necessary logic and a set of mathematical models implemented by electronic systems to control the charging balance of the automotive low-voltage power supply network, connections and functions of systems and components. As a result of a full-scale experiment, charge and discharge graphs, experimental data, current characteristics and dynamics of their changes during operation, experimental time-current dependencies during the operation of each component of a low-voltage power grid were obtained. The results of the work support to improve energy balance of an electrical power network, increase the efficiency and service life cycle of batteries, formulate system and technical requirements for control systems and their subsequent implementation. Versatility solutions are provided for improving management of charge balance car battery.

Crash risk of ESC-fitted passenger cars

Objective: We examined both fatal and injury at-fault crashes of a population of passenger cars fitted with electronic stability control (ESC). Crash rates were calculated in relation to both registration years and mileage. Crash rates were also calculated for a non-ESC car population and crash rate ratios were calculated to compare the crash risk between ESC-fitted and non-ESC-fitted passenger cars.Methods: Passenger car models with and without ESC were identified (ESC-equipped cars: 3,352,813 registration years; non-ESC-equipped: 5,839,946 registration years) and their vehicle information for the period 2009–2013, including mileage (ESC-equipped vehicles: 89.3 billion kilometers; non-ESC-equipped: 72.4 billion kilometers), was drawn from the national Vehicular and Driver Data Register.The registry of Finnish road accident investigation teams was accessed and all fatal at-fault crashes among the cars in the study populations (ESC 97; non-ESC 377) for the period 2009–2013 were analyzed. The motor insurance database includes at-fault crashes leading to injuries and was utilized for analyses (ESC: N = 8,827, non-ESC: N = 21,437).Crash rates and crash rate ratios were calculated to evaluate crash risk of both ESC-equipped and non-ESC-equipped passenger cars. Poisson regression was used to model crash involvement rate ratios both per registration year and per mileage for vehicles with ESC and without ESC, controlling for age and gender of the vehicle owner and vehicle mass.Results: Passenger cars fitted with ESC showed lower crash rates than non-ESC-equipped cars in all crash types studied. In general, the difference in crash rates between ESC-equipped and non-ESC-equipped vehicles was greater when the crashes were compared to the mileage rather than registration years. The mileage-proportional crash rate of ESC-equipped cars was 64% (95% confidence interval, 61%; 67%) lower in run-off-road crashes resulting in injury and as much as 82% (65%; 91%) lower in fatal run-off-road crashes when suicides and disease attacks were not taken into account.Conclusions: Our results show that modern passenger cars provide a significant crash risk reduction, which depends on both ESC and passive safety features introduced. Results also show that exposure evaluation in terms of registration years (or vehicle population) instead of true mileage can provide an overly pessimistic view of the crash risk.

Flammability tests of materials used inside automotive vehicles

This publication presents the flame propagation rates of tested materials according to PN-ISO 3795 requirements. Road vehicles and tractors, agricultural and forestry machinery - Determination of combustibility of materials used inside vehicles for upholstery taken from 15 different passenger car models and assessment of the possibility of using an alternative verification procedure flammability of products used in passenger cars.

Design of an energy efficient car by biomimicry of a boxfish

A boxfish has certain aero/hydrodynamic features in its body shape which makes it more efficient in traveling through the water using less energy. Because of the streamline features of the boxfish, it produces less drag for its movement. So, there is a lot of possibility to design a passenger car by implementing the aerodynamic features on the car shape for improving the energy efficiency. This paper investigates the aerodynamic behavior of a boxfish using both experimental and computational methods. A scaled-up model boxfish was manufactured, and passenger car model was also developed by applied certain aerodynamic features on the car shape and a prototype was manufactured. The models were tested in a wind tunnel condition. The results indicate that the drag coefficient of a boxfish is around 0.24 which is significantly lower than current drag coefficient of a passenger car. The car design inspired by boxfish also energy efficient than a commercially manufactured passenger car. Hence, a boxfish shape can be adapted for achieving low drag and energy efficient motor vehicle design.

Risk of concussion due to head acceleration in rear impact sled tests of passenger automobile seats

Objective: Acceleration-based injury metrics can be useful for quantitatively evaluating risk of concussion (a form of mild traumatic brain injury, or mTBI) after automobile collisions, especially when objective medical findings may be negative, as in many cases of concussion. In the present study, head acceleration data were used to evaluate the risk of concussion or more serious head injury to the driver of an automobile that experiences a rear impact resulting in a forward change in velocity (delta-V) of 15.5 km/h (9.6 mph).Methods: Data were collected from 34 Insurance Institute for Highway Safety (IIHS) rear impact sled tests conducted from 2009 through 2017 for driver seats from 10 passenger car models leading in U.S. sales in 2017. Resultant translational head acceleration data were used to compute the head injury criterion (HIC; HIC15, HIC36) and A-3ms (the 3-ms resultant acceleration criterion utilized by the European New Car Assessment Protocol and others), and maximum resultant translational acceleration (aT). Maximum resultant rotational acceleration (aR) was estimated based on Biofidelic Rear Impact Dummy (BioRID) data from Welch et al. (2010).Results: No sled test included in the study resulted in a HIC15 value exceeding 55, a HIC36 value exceeding 85, A-3ms exceeding 28 g, aT exceeding 28 g, or estimated aR exceeding 1,400 rad/s2. These values are far below published automotive injury risk values (IARV) used to evaluate crashworthiness. Further, contemporary concussion risk curves place the HIC15, aT, aR, and paired combination of aT and aR sustained by the BioRID anthropomorphic test dummy (ATD) in the IIHS tests at a negligible risk of concussion (mTBI).Conclusions: The 15.5 km/h delta-V IIHS rear impact sled tests conducted between 2009 and 2017 for common passenger automobile driver seats resulted in injury metrics associated with minimal risk of concussion or more severe head injuries.

A German Passenger Car and Heavy Vehicle Stock Model: Towards an Autonomous Vehicle Fleet

Automated vehicles are becoming a reality. Many pilot projects have already begun demonstrating the technological capabilities, as public authorities now allow the testing of automated vehicles in real traffic. To smooth the transition from a conventional to an automated fleet, effective fiscal and regulatory policies must be developed by governmental agencies. But at what rate will automated vehicles actually be adopted, and what automation technology will be available for use in new cars joining the national fleet? A national vehicle stock model can be used to answer these questions and to observe the aggregate impact of governmental policies on individual vehicle purchase decisions. In this paper, we present a passenger car and heavy vehicle stock cohort model that forecasts the diffusion of automation technology in Germany. The model uses national data on vehicle stock and vehicle utilization patterns on German freeways and predicts market shares of generic automation levels in predefined instances of a trend scenario. Results point toward market saturation of automated vehicles beyond 2050, with almost 90% of the passenger car fleet being classified as at least partially automatized by this date. The results also suggest that technology diffusion will be faster in the heavy vehicle fleet than in the passenger car fleet. This implies a positive correlation between emission-linked road user charges for heavy vehicles on the freeway network and the renewal rate of the heavy vehicle fleet. The forecast shares of automated vehicles can be used as an input for traffic flow simulations or as a basis for those infrastructure measures and traffic policies that are sensitive to the share of automated vehicles.

Проблеми якості імпортованих вживаних автомобілів в аспекті безпеки експлуатації

Кількісно оцінено модельний масив і якість імпортованих вживаних автомобілів. Результати дослідження будуть інформаційною базою для визначення: найбільш і найменш популярних в Україні (регіоні) моделей; рівня якості певних моделей імпортованих автомобілів; орієнтації сервісних служб (СТО) для освоєння технології технічного обслуговування і ремонту автомобілів, виходячи з обсягу найпоширеніших в Україні моделей імпортованих вживаних легкових автомобілів. За статистичним аналізом результатів сертифікації, проведеної ДП НДІ "СИСТЕМА", досліджено модельний масив імпортованих вживаних легкових автомобілів за моделями і їх характерними дефектами. Встановлено, що найбільш популярними в Україні є моделі легкових автомобілів фірми Renault і автомобільних фірм Німеччини. Оцінено рівень якості імпортованих вживаних автомобілів, серед яких найвищий рівень якості властивий переважно моделям німецьких виробників (Volkswagen, Mercedes-Benz, Audi, BMW) та іншим європейським і японським моделям (Skoda, Peugeot, Ford, Nissan, Toyota, Hyundai), прийнятий рівень якості яких перевищує 0,8. Назагал виділено порівняно високий рівень якості гальмівної системи автомобілів німецьких виробників – у середньому відносна кількість відмов становить 1,01 %, порівняно з 1,63 % для всієї вибірки. Під час планування діяльності сервісних фірм (СТО) доцільно надати перевагу технічному обслуговуванню автомобілів фірм Renault, Volkswagen, Opel, Mercedes-Benz, Skoda, Peugeot, Ford, Citroen.

Influence of Wheel-Rail Contact Stiffness on the H2 Controlled Active Suspension Design

In this work, the mathemtical model of a railway passenger car with conventional and radial-elastic wheels is analyzed. Stochastic excitations are applied to the wheelsets. The local elasticity between the wheel and the rail is modelled by a linearized stiffness behaviour due to geometrical effects to simplify the controller design procedure for H2 analysis. An optimization of the vertical dynamics is performed by reducing the the H2 norms of the dynamic wheel forces while keeping the RMS gain of carbody accelerations at a constant level. It is seen that the controller performs well on the low frequency range where the ride comfort is more pronounced and partially on the high frequency range to suppress the environmental ground vibrations and structure-borne noise.

Dynamic Behaviour of a 7 DoF Passenger Car Model

Conventional vehicle suspension systems, which are passive in nature consists of springs with constant stiffness and dampers with constant damping coefficient. These suspension systems cannot meet the characteristics such as ride comfort, road handing and suspension deflection during abnormal road conditions simultaneously. Active and semi-active suspension systems are the solutions to achieve the desired suspension characteristics. Since, active system is bulky and requires high energy for working, a semi-active suspension system is considered in the present work to analyze vehicle traversing over various road profiles for ride comfort. Mathematical model of a 7 DoF passenger car is formulated using Newton’s method. A semi-active suspension system with skyhook linear control strategy avoids the road excitations at resonant frequencies by shifting the natural frequencies of the model by varying damping coefficients based on the vehicle response for different road conditions where the excitations could be harmonic, transient and random. Modal analysis is carried out to identify the un-damped natural frequencies and mode shapes for different values of damping. The above analyses are carried out through analytical and numerical methods using MATLAB and ANSYS software respectively and the results obtained from both are in good agreement.

Ride Comfort of Passenger Cars on Two-Lane Mountain Highways Based on Tri-axial Acceleration from Field Driving Tests

Having an uncomfortable ride in a vehicle can adversely affect passengers’ travel experience, causing mental and physical fatigue, exacerbating driver fatigue, and increasing the risk of traffic accidents. To determine the level of ride comfort of passenger cars on two-lane mountain highways and the key factors influencing it, in this study, driving tests were performed based on natural driving behavior. Tri-axial acceleration data were collected for various models of small passenger cars, and the peak acceleration values were extracted from the acceleration profiles after they had been filtered using MATLAB filter toolbox. The cumulative frequency curves, characteristic percentiles, and root-mean-square (RMS) values of the tri-axial acceleration were derived. The results revealed that the amplitude of the acceleration, a x , was approximately 50% lower than that of the deceleration, a b . The lateral acceleration, a y , as well as a b and a x , varied significantly for the different car models on different roads. The lack of timely maintenance of a few damaged pavements as well as the existence of speed bumps resulted in “considerable discomfort” to the passengers in the form of vertical acceleration, a z . The amplitudes of the acceleration along the different axial directions could be ranked in the following order: a y > a b > a x > a z ; here, a y , a b , and a z contributed the most to passenger discomfort. It was also concluded that the design speed affects a y and a b significantly. Finally, based on the actual experiences of the drivers and passengers, suggestions were made to adjust the thresholds for a x , a y , and a z .

Aerodynamic coastdown analysis of a passenger car for various configurations

Experimental coastdown analysis were performed on a full scale passenger car model FIAT Linea to obtain the drag coefficients for three different test configurations as engine-cooling airflow closed with smooth underbody, enginecooling airflow closed with detailed underbody, and engine-cooling airflow open with detailed underbody. The comparison of the drag coefficients for all three coastdown configurations were in good agreement with the CFD results and FIAT wind tunnel results. The coastdown tests predicted the model drag coefficients 5.3 % to 7.8 % less than FIAT wind tunnel drag coefficients for three test configurations. The contribution of the engine-cooling airflow and the detailed underbody configuration on the total drag coefficient were measured as 9.6 % ~ 10.4 % and 14.6 % ~ 16.7 %, respectively in the coastdown, FIAT wind tunnel tests and CFD analysis. In the CFD analysis,steady RANS equations were solved by STAR-CCM+ code. The turbulence model was selected as realizable k-e two layer model. Model surface pressure contours were compared for all three test.

A Durability Study on the Bumper of Mini Vehicle by Shape through Simulation Analysis

Objectives: Studies on aluminum alloy bumpers applied to vehicles are being actively carried out. This study aims at investigating the durability according to the compact car bumpers per shape. Methods/Statistical Analysis: In this study, two types of compact car bumper models were designed as 3D modeling and then simulation structural analyses were performed by the finite element analysis program of ANSYS. The durability of the bumper model of light passenger car by each configuration is investigated through this study. The analyses of structure and vibration on the bumper model of light passenger car by configuration are carried out. Findings: Although all comparison variables were shown to be smaller when the bumper model 1 was compared with the bumper model 2, the stress distribution was observed to be wider so that the reinforcement of material or the change of design for improvement is considered necessary. Through this study result, the deformation, equivalent stress due to natural frequency are investigated by each bumper model of light passenger car. According to the study results, the bumper model 1 exhibited a better durability compared with model 2, and hence is considered to be a safe and more suitable model for the vehicle application. The results are considered to be able to contribute to the development of more advanced bumpers having durability. Improvements/Applications: It is considered that the data obtained through this study can be utilized for the design of the bumper having an improved durability compared with the existing bumpers.

Simulation Analysis of the Effects of a Rail Vehicle Running with Wheel Flat

This contribution deals with the computer simulation and the follow analysis of the rail vehicle running with wheel flat. It comprises of two parts. The first part addresses to the problem of rail vehicle operational, which wheel is damaged. There are several types of wheel damages. In this work the wheel flat problem is introduced. Generally, the rail vehicle running with wheel flat is adverse because the track can be shopworn, some parts of rail vehicle can be damaged and also operational condition for passenger or goods (depending on kind of rail vehicle) can be worse markedly. There is also included a system of forces and accelerations measurement during rail vehicle running on the given track section. The second part includes computer modelling and simulation of this phenomenon. Analyses were focused on the assessemnt of the rail vehicle motion smoothness and its damaging impact on the track. For this, there was created computer model of a twin-bogies passenger car, which the one wheel was modelled as damaged, i.e. wheel flat. Then, there were performed simulations of the rail vehicle running at various speeds. The passenger car was run on the straight track without irregularities in order to avoid adding excitation. Subsequently, values of the vertical wheel forces of the wheel with flat was evaluated.

A stock-flow cohort model of the national car fleet

Various regulatory and fiscal policy instruments are in force to reduce the amount of greenhouse gases and local pollutants emitted by private cars. The incentives operate primarily—or exclusively—on the newest generation of cars. But how fast will technological developments affecting new vehicle models penetrate into the car fleet? The speed at which the adverse effects of private car use will be mitigated through the normal vehicle renewal process, or through an accelerated one, carries considerable interest. Suitable modelling tools are needed. This paper aims to demonstrate the usefulness and flexibility of a bottom-up stock-flow modelling approach to private car fleet forecasting and policy analysis. In the BIG model of the Norwegian automobile fleet, the annual stocks and flows characterising the car fleet are specified as matrices of 682 mutually exclusive and exhaustive cells, formed by cross-tabulations between 22 vehicle segments and 31 age classes. New car registrations follow from a disaggregate generic discrete choice model based on two decades of complete sales data for individual passenger car models. Example projections are presented onto the 2050 horizon under a low carbon fiscal policy scenario as well as a business-as-usual scenario. The fiscal policy is seen to make a large difference in terms of long term fuel consumption and CO2 emissions. Stock-flow cohort modelling of the automobile fleet is a powerful and handy tool for policy analysis. Even quite simple and straightforward accounting relations may provide important insights into the dynamics of fleet development. It is possible to incorporate, into the stock-flow modelling framework, interesting and useful behavioural relations, explaining aggregate automobile ownership and travel demand, scrapping and survival rates, or consumer choice in the market for new cars.

Can new passenger cars reduce pedestrian lower extremity injury? A review of geometrical changes of front-end design before and after regulatory efforts

ABSTRACTObjective: Pedestrian lower extremity represents the most frequently injured body region in car-to-pedestrian accidents. The European Directive concerning pedestrian safety was established in 2003 for evaluating pedestrian protection performance of car models. However, design changes have not been quantified since then. The goal of this study was to investigate front-end profiles of representative passenger car models and the potential influence on pedestrian lower extremity injury risk.Methods: The front-end styling of sedans and sport utility vehicles (SUV) released from 2008 to 2011 was characterized by the geometrical parameters related to pedestrian safety and compared to representative car models before 2003. The influence of geometrical design change on the resultant risk of injury to pedestrian lower extremity—that is, knee ligament rupture and long bone fracture—was estimated by a previously developed assessment tool assuming identical structural stiffness. Based on response surface generated from simulation results of a human body model (HBM), the tool provided kinematic and kinetic responses of pedestrian lower extremity resulted from a given car's front-end design.Results: Newer passenger cars exhibited a “flatter” front-end design. The median value of the sedan models provided 87.5 mm less bottom depth, and the SUV models exhibited 94.7 mm less bottom depth. In the lateral impact configuration similar to that in the regulatory test methods, these geometrical changes tend to reduce the injury risk of human knee ligament rupture by 36.6 and 39.6% based on computational approximation. The geometrical changes did not significantly influence the long bone fracture risk.Conclusions: The present study reviewed the geometrical changes in car front-ends along with regulatory concerns regarding pedestrian safety. A preliminary quantitative benefit of the lower extremity injury reduction was estimated based on these geometrical features. Further investigation is recommended on the structural changes and inclusion of more accident scenarios.