Chinmoy Pal

Development of a Brake-Operated Pre-Crash Seatbelt System and Performance Evaluation

This studys aim was to evaluate the effectiveness of a brake operated pre-crash seatbelt system by considering the dynamic behavior of the vehicle combined with the safety performance of the vehicle during the crash. The experimental results were used in numerical simulations as the initial conditions for calculating parameters related to vehicle safety during a crash event. The results indicated that the brake operated pre-crash seatbelt system has the potential to reduce injury parameters even if emergency braking is applied prior to a crash.

Improvement of injury severity prediction (ISP) of AACN during on-site triage using vehicle deformation pattern for car-to-car (C2C) side impacts

ABSTRACT Objective: The Advanced Automatic Crash Notification (AACN) system needs to predict injury accurately, to provide appropriate treatment for seriously injured occupants involved in motor vehicle crashes. This study investigates the possibility of improving the accuracy of the AACN system, using vehicle deformation parameters in car-to-car (C2C) side impacts. Methods: This study was based on car-to-car (C2C) crash data from NASS-CDS, CY 2004–2014. Variables from Kononens algorithm (published in 2011) were used to build a “base model” for this study. Two additional variables, intrusion magnitude and max deformation location, are added to Kononens algorithm variables (age, belt usage, number of events, and delta-v) to build a “proposed model.” This proposed model operates in two stages: In the first stage, the AACN system uses Kononens variables and predicts injury severity, based on which emergency medical services (EMS) is dispatched; in the second stage, the EMS team conveys deformation-related information, for accurate prediction of serious injury. Results: Logistic regression analysis reveals that the vehicle deformation location and intrusion magnitude are significant parameters in predicting the level of injury. The percentage of serious injury decreases as the deformation location shifts away from the driver sitting position. The proposed model can improve the sensitivity (serious injury correctly predicted as serious) from 50% to 63%, and overall prediction accuracy increased from 83.5% to 85.9%. Conclusion: The proposed method can improve the accuracy of injury prediction in side-impact collisions. Similar opportunities exist for other crash modes also.

An insight of World Health Organization (WHO) accident database by cluster analysis with self-organizing map (SOM)

ABSTRACT Objective: Road crashes are increasing every year in low- and middle-income countries compared to high-income countries, which show decreasing trends. One theory may be because of differences in enforcement of laws, vehicle safety, road standards, and many other factors. A detailed review was made of 5 death trends (total number of deaths/100,000 population and percentages of 4-wheeler, pedestrian, motorized 2/3-wheeler, bicyclist) and the underlying patterns in different countries and regions across the world. This review was done to understand the main reasons for the variances to focus on efficient improvement strategies related to future vehicle and road safety issues. Methods: A self-organizing map (SOM) technique is used to map the nonlinear relationships among different attributes. Overall, 176 countries with 44 attributes were considered from the World Health Organizations (WHO) Global Status Report on Road Traffic Crashes database. Of the 44 attributes, 5 related to accident deaths were considered as response attributes. Results: Very distinct and unique cause–effect patterns for 3 clusters were observed from SOM results. High-income countries were found to have a lower total number of deaths/100,000 population. One theory espouses that this was due to those countries maintaining high vehicle standards and policies, whereas it was quite a different situation for low-income countries. Even though helmet laws were available in Association of South East Asian Nations + 6 (ASEAN + 6) countries, the percentage of 2/3-wheeler deaths may be higher due a lack of enforcement of those laws. Percentage of deaths involving 4-wheeler vehicles was higher in certain countries in the Persian Gulf, the United States, Australia, and New Zealand. This may be due to the fact that these countries have a number of rural areas where drivers drive at highway speeds versus some lower income countries with more urban areas where drivers operate vehicles at slower speeds. Countries with a lack of laws protecting bicyclists saw higher death percentages among bicyclists. The percentage of bicyclist deaths was also higher in areas with no helmet requirement and no investment in infrastructure improvements. The percentage of pedestrian deaths was high when there was no policy to separate road users, especially in low-income African countries. Deaths can be reduced by enforcement of laws and practicing good safety standards related to road traffic. Conclusions: Future vehicle and road safety strategies should consider using advanced statistical tools like SOM to advance safety. Based on a triple-layer (vehicle, infrastructure, and society) safety approach, strict regulations and enforcement are effective measures to reduce fatalities in low- and middle-income countries. On the other hand, introduction of more advanced vehicle technologies will be useful in countries with high gross national incomes (GNIs). Hence, a proper balance of different countermeasures based on economic zones could be effective to reduce total world traffic casualties.

Flex-PLI application to high-bumper vehicles - optimization of supplemental weight

The Flexible Pedestrian Legform Impactor (Flex-PLI) was developed to evaluate the risk of pedestrian lower extremity injuries. However, it has been pointed out that the post-crash kinematics of the Flex-PLI differs from those of a human body when it is hit by high-bumper vehicles. This paper describes the feasibility of applying the Flex-PLI to a wide range of vehicle types by adding a supplemental weight. The following aspects are discussed in this regard: A human body finite element (FE) model analysis shows that the upper body of the Flex-PLI is not involved in tibia and knee ligament injury indexes in the first contact with a high-bumper vehicle. A rigid bar model is introduced and its rotational energy ratio is formulated. The rotational energy ratio is employed to evaluate the post-crash kinematics of the Flex-PLI and a human leg model. The feasibility of adding a supplemental weight to the Flex-PLI with regard to the bumper height is discussed. Language: en

Analysis of Pedestrian Kinematics and Injury Mechanism in Real World Accidents

Post-impact pedestrian kinematics is complex and depends on various factors such as impact speed, height of the pedestrian, front-end profile of the striking vehicle and pedestrian posture, among others. The aim of this study is to investigate the main factors that determine post-crash pedestrian kinematics. A detailed study of NASS-PCDS (National Automotive Sampling System—Pedestrian Crash Data Study) showed that the vehicle–pedestrian interaction in frontal crashes can be categorized into four types. Pedestrian-vehicle size ratio and the impact speed are the two most influential factors that determine post crash pedestrian kinematics. The findings from the NASS-PCDS study were also confirmed and verified with the help of numerical simulations performed using two modified JAMA human FE models. An adult model (male, 175 cm and 72 kg) and a properly scaled child model (6 years old, 120 cm and 24.5 kg) were effectively utilized to investigate the post-crash kinematics in different conditions.