Francisco J Lopez-Valdes

• PhD
• Professor (Assistant) at Comillas Pontifical University

Objective: The objective of this article is to analyze the kinematics and dynamics of restrained postmortem human surrogates (PMHS) exposed to a nearside oblique impact and the injuries that were found after the tests. Methods: Three male PMHS of similar age (64 ± 4 years) and anthropometry (weight: 61 ± 9.6 kg; stature: 172 ± 2.7 cm) were exposed...

Objectives: The objective of this study was to determine the potential chest injury benefits and influence on occupant kinematics of a belt system with independent control of the shoulder and lap portions. Methods: This article investigates the kinematics and dynamics of human surrogates in 35 km/h impacts with 2 different restraints: a pretensioni...

Previous research has suggested that the pediatric ATD spine, developed from scaling the adult ATD spine, may not adequately represent a child's spine and thus may lead to important differences in the ATD head trajectory relative to a human. To gain further insight into this issue, the objectives of this study were, through non-injurious frontal sl...

As pediatric PMHS data are extremely limited, evidence of kinematic differences between pediatric ATDs and live humans comes from comparison of laboratory data to field crash data. Despite the existence of regulations intended to prevent head injuries, these remain the most common serious injuries sustained by children in crashes. In this study, ni...

Quantifying the kinematics of the human spine during a frontal impact is a challenge due to the multi-degree-of-freedom structure of the vertebral column. This papers reports on a series of six frontal impacts sled tests performed on three Post Mortem Human Surrogates (PMHS). Each subject was exposed first to a low-speed, non-injurious frontal impa...

Objective: This study aims to establish best practices and guidelines to ensure that experimental research utilizing Postmortem Human Subjects (PMHS) for injury prevention adheres to relevant ethical principles, which are also commonly accepted in research involving human tissues and living subjects. Furthermore, it reviews existing literature to...

Introduction: The global motorcycle market has grown significantly, with over 770 million vehicles estimated to be in use worldwide. Motorcycle-related road traffic deaths in low and middle-income countries (LMICs) like Colombia are concerning, comprising 30% of all reported fatalities. Cartagena has an average of 70 motorcycle-related deaths annu...

Contemporary research has pointed out that while newer cars are contributing to the decrease of AIS2+ and AIS3+ injuries in several body regions, this effect is not shown for thoracic injuries like rib or sternal fractures. The objective of this study is to assess the effectiveness of advanced seat belt systems incorporating pre-tensioners and load...

Introduction: Chest deformation has been proposed as the best predictor of thoracic injury risk in frontal impacts. Finite Element Human Body Models (FE-HBM) can enhance the results obtained in physical crash tests with Anthropometric Test Devices (ATD) since they can be exposed to omnidirectional impacts and their geometry can be modified to refle...

Objective: The objective of this study is to analyze the 6 degrees of freedom (DOF) motion of the spine using the finite helical axis (FHA) in three postmortem human surrogates (PMHS) sled tests. Methods: The sled test configurations corresponded to a 30° nearside oblique impact at 35 km/h. Two different restraint system versions (RSv) were used....

Regulation ECE-22.05/06 does not require a helmet penetration test. Penetration testing is controversial since it has been shown that it may cause the helmet to behave in a non-desirable stiff way in real-world crashes. This study aimed to assess the effect of the penetration test in the impact performance of helmets. Twenty full-face motorcycle he...

Objective: The present study has three objectives: First, to analyze the chest deflection measured in nearside oblique tests performed with three post mortem human subjects (PMHS). Second, to assess the capability of a HBM to predict the chest deflection sustained by the PMHS. Third to evaluate the influence on chest deflection prediction of subje...

Oblique impacts of the helmet against the ground are the most frequent scenarios in real-world motorcycle crashes. The combination of two factors that largely affect the results of oblique impact tests are discussed in this work. This study aims to quantify the effect of the friction at the interface between the headform and the interior of a motor...

The objective of this study is to analysis of accident of motorcyclists on Bogotá roads in Colombia. For detection of conditions related to crashes and their severity, the proposed model develops the strategies to enhance road safety. In this context, data mining and machine learning techniques are used to investigate 34,232 accidents by motorcycli...

Objective: This study aimed to identify the association between behavioral factors and crashes of motorcycle taxi riders using the Motorcycle Rider Behavior Questionnaire (MRBQ). Methods: This study was a cross-sectional survey of motorcycle taxi riders in Cartagena. The MRBQ was adapted to the socio-cultural context and contained 45 items. The sur...

Cervical pain and injuries are a major health problem globally. Existing neck injury criteria are based on experimental studies that included sled tests performed with volunteers, post-mortem human surrogates and animals. However, none of these studies have addressed the differences between young adults and elderly volunteers to date. Thus, this wo...

Motorcyclists account for more than 380,000 deaths annually worldwide from road traffic accidents. Motorcyclists are the most vulnerable road users worldwide to road safety (28% of global fatalities), together with cyclists and pedestrians. Approximately 80% of deaths are from low- or middle-income countries. Colombia has a rate of 9.7 deaths per 1...

Objective Crashworthiness assessments in the United States (U.S.) and the European Union (EU) include a large number of safety regulations and consumer testing programs. However, safety standards and testing procedures differ between the two regions. Not much research has been done in relation to this topic, because it has always been assumed that...

Permanent monitoring of real-world crashes is important to identify injury patterns and injury mechanisms that still occur in the field despite existing regulations and consumer testing programs. This study investigates current injury patterns at the MAIS 3+ level in the accident environment without limiting the impact direction. The approach consi...

CO2 emissions are one of the major contributors to global warming. The variety of emission sources and the nature of CO2 hinders estimating its concentration in real time and therefore to adopt flexible policies that contribute to its control and, ultimately, to reduce its effects. Spain is not exempted from this challenge and CO2 emissions are pub...

Objective: To understand which users' characteristics influence their preferences in the selection of vehicle seating configurations and positions across different traveling scenarios involving a fully automated vehicle (FAV). Methods: Participants (n = 730) completed an online survey in which they were asked to imagine traveling in a FAV across...

In 2016, Colombia’s position regarding motorcyclist fatalities per 100,000 inhabitants was tenth worldwide and second in South America. In the seven years from 2012-2018, the proportion of deceased and injured motorcyclists among all road users was 50%. To analyse the significant aspects of the accident rate of motorcyclists in Colombia from 2016 t...

Objective: The goal of the study was to assess the feasibility of a safe crash environment for volunteer tests in reclined seating positions. An iterative multimodal approach was chosen, consisting of full-body human body model (HBM) simulations, anthropomorphic test device (ATD) physical testing, and volunteer testing. Methods: To estimate a nonin...

Objective: Analyze the road crashes in Cartagena (Colombia) and the factors associated with the collision and severity. The aim is to establish a set of rules for defining countermeasures to improve road safety. Methods: Data mining and machine learning techniques were used in 7894 traffic accidents from 2016 to 2017. The severity was determined be...

770 million motorcycles are estimated on the roads. Motorcyclists represent more than 380,000 annual deaths worldwide. 28% of the global fatalities in the roads in 2016. With the increase of the accident rate, studies have been developed within the scientific literature. Bibliometric analysis is applied in the field of motorcycle safety in order to...

Objective: This study aimed to understand seating configuration and position preferences in a fully automated vehicle (FAV) across 7 hypothetical traveling scenarios. Methods: Participants completed an online survey in which they were asked to imagine traveling in an FAV across 7 hypothetical traveling scenarios and asked to select 1 of 5 seating c...

The goal of this study was to quantify the effect of improving the geometry of a human body model on the accuracy of the predicted kinematics for 4 post-mortem human subject sled tests. Three modifications to the computational human body model THUMS were carried out to evaluate if subject personification can increase the agreement between predicted...

Objective: The goal of the study was to develop experimental chest loading conditions that would cause up to Abbreviated Injury Scale (AIS) 2 chest injuries in elderly occupants in moderate-speed frontal crashes. The new set of experimental data was also intended to be used in the benchmark of existing thoracic injury criteria in lower-speed collis...

Objective: The objective of this paper is to compare the performance of forward-facing Child Restraint Systems (CRS) mounted on two different seats. Methods: Two different ATD (Anthropomorphic Test Device) sizes (P3 and P6), using the same child restraint system (a non-ISOFIX high-back booster seat) were exposed to the ECE R44 regulatory decelerati...

The aim of this study is to determine the risk of fatal head injury for adult pedestrians struck by a passenger car. The research focuses on the wrap around distance (WAD) and vehicle front geometry, including the effects of pedestrian height, impact speed and other parameters that directly influence the head impact against the vehicle. Data from G...

Objective: The goal of the study is to compare the kinematics and dynamics of the THOR dummy in a frontal impact under the action of 2 state-of-the-art restraint systems. Methods: Ten frontal sled tests were performed with THOR at 2 different impact speeds (35 and 9 km/h). Two advanced restraint systems were used: a pretensioned force-limiting b...

Objective: The goal of this study is to characterize the in situ 6-degree-of-freedom kinematics of the head, 3 vertebrae (T1, T8, and L2), and the pelvis in a 40 km/h frontal impact. Methods: Three postmortem human surrogates (PMHS) were exposed to a deceleration of 15 g over 125 ms and the motion of selected anatomical structures (head, T1, T8,...

The goal of this study is to characterize the in vitro dynamic response of the human thoracic spine undergoing flexion in the sagittal plane. Eight human functional spinal units (FSU) were harvested from four donors (7, 15, 48 and 52 years old). FSU consisted of three contiguous vertebrae (T2-T4 and T7-T9), representing two different regions along...

Contemporary research has pointed out the differences observed in the kinematics of pediatric dummies and rear-facing child restraint systems (CRS) between the regulatory bench used in FMVSS 213 and CMVSS 213 regulations and real vehicle seats. The objective of this study was to compare the performance of forward-facing CRS between a variant of the...

In far-side impacts, head contact with interior components is a key injury mechanism. Restraint characteristics have a pronounced influence on head motion and injury risk. This study performed a parametric examination of restraint, positioning, and collision factors affecting shoulder belt retention and occupant kinematics in far-side lateral and o...

Head injuries are the most common severe injuries sustained by pediatric occupants in road traffic crashes. Preventing children from adopting positions that can result in an increased injury risk due to unfavorable interactions with the restraints is fundamental. The objective of this paper was to assess the effect of a head support system (SS) on...

Head injuries are the most frequent and severe injuries sustained by children in motor vehicle crashes regardless of age, restraint type and direction of impact force. Recent investigations have shown that these injuries are likely related to the direct contact of the head with the interior components of the vehicle. The present study evaluates the...

Powered two-wheelers (PTWs - mopeds, motorcycles, and scooters) remain the most dangerous form of travel on today's roads. This study used hospital discharge data from eight European countries to examine the frequencies and patterns of injury among PTW users (age≥14 years), the predicted incidence of the loss of functional ability, and the mechanis...

This paper quantifies pediatric thoracoabdominal response to belt loading to guide the scaling of existing adult response data and to assess the validity of a juvenile porcine abdominal model for application to the development of physical and computational models of the human child. Table-top belt-loading experiments were performed on 6, 7, and 15...

The goal of this article is to propose a new methodology to estimate the sagittal plane displacement of the head, spine, and pelvis of a 6-year-old (6YO) occupant during a high-speed frontal impact. Research has shown major discrepancies between the spinal kinematics of current pediatric anthropomorphic test devices and humans during frontal impact...

Injury prevention research often entails describing the severity of injuries or controlling for the severity of injuries when comparing outcomes. Basically, injury severity scores are required to either prioritize interventions at the patient level (e.g., triage, medical care) or population level as well as when evaluating the effectiveness of inju...

Previous research has quantified differences in head and spinal kinematics between children and adults restrained in an automotive-like configuration subjected to low speed dynamic loading. The forces and moments that the cervical spine imposes on the head contribute directly to these age-based kinematic variations. To provide further explanation o...

This study investigates the performance of a 3-point restraint system incorporating an inflatable shoulder belt with a nominal 2.5-kN load limiter and a non-inflatable lap belt with a pretensioner (the "Airbelt"). Frontal impacts with PMHS in a rear seat environment are presented and the Airbelt system is contrasted with an earlier 3-point system w...

Understanding pediatric occupant postures can help researchers indentify injury risk factors, and provide information for prospective injury prediction. This study sought to observe lateral head positions and shoulder belt fit among older child automobile occupants during a scenario likely to result in sleeping - extended travel during the night. A...

A growing body of literature points out the relevance of the thoracic spine dynamics in understanding the thorax-restraint interaction as well as in determining the kinematics of the head and cervical spine. This study characterizes the dynamic response in bending of eight human spinal specimens (4 pediatric: ages 7 and 15 years, 4 adult: ages 48 a...

This study assesses the impact on safety of a system designed to enhance sleep in car passengers. The system holds the head posteriorly and limits its rotation in the sagittal and frontal planes, modifying the occupant's head position. This device may have an influence on the interaction between the occupant and the vehicle restraint systems. It wa...

While rupture of the aorta is a leading cause of sudden death following motor vehicle crashes, the specific mechanism that causes this injury is not currently well understood. Aortic ruptures occurring in the field are likely due to a complex combination of contributing factors such as acceleration, compression of the chest, and increased pressure...

Despite increases in helmet use, powered two wheelers (PTWs - mopeds, motorcycles, scooters) remain the most dangerous form of travel on today's roads. This study sought to identify helmet use rates, mortality rates, and injury patterns among PTW users in Spain using a cross-sectional, ecological study design. Overall helmet use rates for 2005-2008...

Traumatic brain and skull injuries are the most common serious injuries sustained by children in motor vehicle crashes. The spine dictates the position and orientation of the head during the impact. Research has shown major discrepancies between the spinal kinematics of current pediatric Anthropomorphic Test Devices and humans during frontal impact...

Research on the risk of motor vehicle injuries and their relationship with the amount of travel has been only partially analyzed. The few individual exposure assessments are related to very specific subsets of the driving and traveling populations. This study analyzes the relationship between kilometers traveled and hospitalization due to motor veh...

Out of the 50,000 yearly road traffic deaths in the European Union (formed by 27 European countries and commonly designated as EU-27), some 8500 are pedestrians. While some studies focus on the increased risk for pedestrian mortality compared to other road users, there is a dearth of information on injury patterns that could be used to prioritize i...

The objectives of this study were to examine the axial response of the clavicle under quasistatic compressions replicating the body boundary conditions and to quantify the sensitivity of finite element-predicted fracture in the clavicle to several parameters. Clavicles were harvested from 14 donors (age range 14-56 years). Quasistatic axial compres...

This article presents the response of a child-size postmortem human subject using a booster seat in a series of three frontal impact sled tests. A 54-year-old female cadaver was seated in a booster seat in the rear seat of a buck representing a mid-sized American sedan. Two different restraint systems (conventional belt and pretensioning, force-lim...

To investigate whether the occupants in vehicles with better safety ratings according to EuroNCAP sustain fewer fatal and severe injuries than occupants in vehicles with worse experimental safety ratings when in frontal crashes. Case-control study. A representative sample of crashes in Britain from 1996 to 2008 as gathered in the Cooperative Crash...

Pediatric Anthropomorphic Test Devices (ATD) provide a reasonable approximation predicting maximum head excursion. However, the exact trajectory followed by the human head and the flexible human spine cannot be replicated by the stiff spine of ATD. Lack of knowledge on pediatric whole body kinematics during a frontal impact precludes the developmen...

The Hybrid III 6-year-old ATD has been benchmarked against adult-scaled component level tests but the lack of biomechanical data hinders the effectiveness of the procedures used to scale the adult data to the child. Whole body kinematic validation of the pediatric ATD through limited comparison to post mortem human subjects (PMHS) of similar age an...

Frontal-impact airbag systems have the potential to provide a benefit to rear seat occupants by distributing restraining forces over the body in a manner not possible using belts alone. This study sought to investigate the effects of incorporating a belt-integrated airbag ("airbelt") into a rear seat occupant restraint system. Frontal impact sled t...

With the adoption of effective passive safety measures to protect occupants in frontal crashes, interest on advancing side impact crashworthiness is raising. Our goal was to assess the main risk factors for severe injuries among adult front-seat passengers in side crashes. USA NASS CDS data (1998-2005) on side crashes were analyzed. Belted drivers...

Rear seat adult occupant protection is receiving increased attention from the automotive safety community. Recent anthropomorphic test device (ATD) studies have suggested that it may be possible to improve kinematics and reduce injuries to rear seat occupants in frontal collisions by incorporating shoulder-belt force-limiting and pretensioning (FL+...

As obesity rates increase, the protection of obese occupants will become increasingly important in vehicle and restraint design. As a first step in this effort, this study seeks to compare the kinematics, dynamics, and injuries of obese post mortem human surrogates (PMHS) to (approximately) 50(th) percentile adult male PMHS in frontal impact sled t...

Crash protection for an aging population is one of the primary drivers of contemporary passive safety research, yet estimates of the potential benefit of age-optimized systems have not been reported. This study estimates the number killed and injured in traffic crashes due to the age-related reduction in tolerance to loading. A risk-saturation mode...

Road traffic accidents constitute the first cause of unintentional injury death in the European Union (EU). In EU-25, an estimated 43,000 people die every year due to motor vehicle crashes. Nevertheless, road traffic injuries can be prevented and their consequences can be alleviated if the appropriate practices, policies, strategies and road safety...

Even when injury prevention is not the primary focus of a new policy, it is important to consider the implications for injury risk

We investigated whether the rating obtained in the EuroNCAP test procedures correlates with injury protection to vehicle occupants in real crashes using data in the UK Cooperative Crash Injury Study (CCIS) database from 1996 to 2005. Multivariate Poisson regression models were developed, using the Abbreviated Injury Scale (AIS) score by body region...

Powered two wheelers (PTWs) riders are one of the most vulnerable groups of road users. Roadside barriers work quite effectively for passenger cars, but sometimes they are dangerous for motorcyclists, especially guard-rails. These accidents are investigated by means of an analysis of the DGT Spanish National Accident Database and reviewing differen...

uantifying the kinematics of the human spine during a frontal impact is a challenge due to the multi-degree-of-freedom structure of the vertebral column. This papers reports on a series of six frontal impacts sled tests performed on three Post Mortem Human Surrogates (PMHS). Each subject was exposed first to a low-speed, non-injurious frontal impac...