Browse Topic: Crashes

Items (6,285)

Low Speed Bumper System Impact Variation Study

2026-01-0474To be published on 04/07/2026

Variation studies are an important part of the product development (PD) process. They help to understand and estimate real-world deviation from design nominal parameters, optimize designs for robustness, reliability, and cost-efficiency. CAE and Virtual tools enable us to simulate a great number of different variation types and capture the full bandwidth of actual field performance - rather than the validation from a limited number of physical tests. In this study, the effects of various factors on vehicle performance during low-speed impacts, utilizing a Design of Experiments (DOE) approach have been investigated through virtual simulation. Low-speed impacts, typically defined as collisions occurring at speeds less than 2.5 mph, are critical for understanding vehicle insurability and compliance with regulatory standards. The factors examined include vehicle impactor position, impact speed, and angle of collision, part thickness variation, material card variation. The DOE methodology

Suravaram, Raghu Mohan Reddy, Islam, ABM Iftekharul, Larson, John, Tehrani, Babak, Koch, Lisa, Mathur, Mohit Sain

Multi-Physics Topology Optimization and Machine Learning Surrogates for Lightweight Cast Automotive Parts

2026-01-0510To be published on 04/07/2026

This paper proposes an integrated optimization framework for lightweight cast vehicle structures by combining Multi-Physics Topology Optimization (MPTO) with machine learning (ML)-driven surrogate modeling. Conventional structural optimization approaches often rely on simplified load cases—such as 3 g inertial loading, frame torsion, or bending—rather than capturing the true complexity of performance-critical conditions like crashworthiness and fatigue durability. As a result, designs optimized for a single criterion frequently degrade in other performance areas, leading to costly redesigns or over-engineered solutions. The proposed methodology introduces MPTO through four structured steps that progressively build design fidelity. Step 1 establishes a baseline primitive topology optimization workflow using a standardized package checklist, ensuring that the design domain, boundary conditions, constraints, and key manufacturing rules are consistently defined as the foundation for

Kim, Hyosig, Senkowski, Andres, Gona, Kiran, Saroha, Lalit, Boraiah, Mahesh

Optimal Control Analysis of Minimum-Time Maneuvers for Vehicles Recovering from Instability

2026-01-0218To be published on 04/07/2026

Vehicles may enter highly unstable dynamic states due to lateral collisions, sudden loss of grip, or extreme steering disturbances. When such instability arises in congested road sections where obstacle avoidance is required, the safety risk to both the ego vehicle and surrounding traffic escalates significantly. In such scenarios, the vehicle must not only regain stability but also navigate the roadway in the shortest feasible time to prevent secondary collisions. This paper investigates the minimum-time maneuver of a vehicle starting from an unstable dynamic condition and constrained to travel within prescribed road boundaries. A single-track vehicle model with combined-slip nonlinear tire model is employed to capture the vehicle dynamics under high slip conditions. Phase-plane analysis is conducted to reveal how control inputs reshape the system’s vector field and influence the possibility and speed of stability recovery. An optimal control problem is formulated to compute the

Leng, Jiatong, Yu, Liangyao, Wang, Yongxin, You, Weijie, Li, Ziang, Jin, Zhipeng

Development of Automotive Hood Using Multi-Material Double Injection Molding

2026-01-0476To be published on 04/07/2026

Introduction: The automotive hood is a critical closure component that must meet structural, safety, and styling requirements. Traditional metal hoods are increasingly being replaced or supplemented by polymer-based designs due to advancements in material technology and manufacturing methods. Among these, multi-material double injection molding presents a promising alternative to reduce production time and cost while achieving performance compliance. Aim: This study aims to develop an automotive hood using a hybrid plastic combination through a double-shot injection molding process. The focus is on evaluating the structural feasibility of such designs under regulatory and OEM-defined stiffness and crashworthiness performance targets. Purpose: The objective is to investigate the compatibility of different thermoplastic materials for outer and inner skin layers in achieving structural rigidity, impact resistance, and manufacturing efficiency. The approach targets the consolidation of

GANESAN, KARTHIKEYAN, Seok, Sang Ho, Jo, Hyoung Han

CAE Acceleration With Machine Learning For Results Prediction

2026-01-0488To be published on 04/07/2026

Industries are following a tedious product development cycle for developing their product. In product development major steps includes design ideas, Drawings, CAD, CAE, Testing and design improvement cycle. This is a monotonous process and takes time which impacts on its time to deliver product and cost on development. Now a days industries are fast growing and targeting to reduce development cycle time and cost. AIML is impacting almost all areas in the industry and significantly reducing efforts time and cost. To make use of AIML in CAE, Altair Physics AI is an effective tool. To ensure the design of product traditional way is to develop a CAD of the product, develop, perform CAE and analyze performance. If we consider CAE procedure it is time consuming process which includes FEA model build, applying boundary conditions, running simulation and analyzing results which could take minutes to hours. By using ML with Physics AI we can make predictions on new design of the product in

Dangare, Anand Manohar, Kulkarni, Mandar

Design and Simulation Analysis of an Integrated Honeycomb-filled Front Bumper for a Special Vehicle

2026-01-0475To be published on 04/07/2026

In frontal collisions of automobiles, the bumper beam at the front of the vehicle plays a crucial role in absorbing energy and protecting the vehicle body during a collision. To enhance the collision resistance of a specific type of special vehicle with a non-load-bearing body structure, this paper focuses on this type of vehicle and conducts a study on the design and collision performance of an integrated vehicle front bumper-impact beam structure based on aluminum alloy additive manufacturing technology. A novel bumper structure is proposed, which integrates the front bumper and the front impact beam of the vehicle and is integrally formed using aluminum alloy additive manufacturing technology. This integrated structure is directly connected to the vehicle frame. Firstly, based on the appearance of the special vehicle body and the form of the front impact beam of traditional passenger vehicles, an integrated design of the vehicle front bumper-impact beam structure is carried out and

王, Xufan, Yuan, Liu-kai, Zhang, tangyun, Wang, Tao, Zhang, Ming, Wang, Liangmo

Predictive AEB Activation for Secondary Collision Risk Reduction

2026-01-0518To be published on 04/07/2026

Although the evaluation criteria of New Car Assessment Programs (NCAP) continue to evolve, they still predominantly focus on one-to-one collision scenarios. However, accident analyses indicate that in real-world traffic environments, particularly at intersections with multi-lane arterial roads, complex situations involving multiple vehicles are common, and there exists a significant risk of secondary side collisions occurring immediately after Autonomous Emergency Braking (AEB) activation. This study aims to predict and mitigate such secondary collision risks by proposing a control strategy that adjusts braking timing and stopping position based on the motion information of multiple crossing vehicles. A control algorithm was developed to estimate the likelihood of secondary collisions and determine optimal intervention parameters. The proposed system was evaluated using a sensor-equipped test vehicle and numerical simulations. Results demonstrated a tendency to reduce secondary

Kobayashi, Fumiya, Fukuda, Kentaro, TANI, HIROAKI

Curb Impact: Non-linear structural FE analyses in Multibody Dynamics Models

2026-01-0219To be published on 04/07/2026

In a few extreme customer abuse load cases such as Curb Impact and Potholes, automotive structures see non-linear (plastic) deformations as well as large rigid body motion. The load cases can be simulated by crash analysis tools such as LS-Dyna or multi-body dynamics analysis tools like Ansys Motion. The crash analysis has a better representation of structural compliances including large deformation with large rigid body motion. However, it requires a well-defined FE model and suspension multi-body models in detail. Furthermore, it takes a long time to get a result. On the other hand, the multi-body dynamics approach is very quick to get a result, while it has a limitation of representing structural compliance. The limitation is true in representing structural non-linearity such as large deformation associated with plastic yielding. In this study, a curb impact simulation was performed using the multi-body dynamic approach with nonlinear structural analysis capabilities included in

Hong, Hyung-Joo, Kim, Wangoo

Game-Changing Flow-Centric Traffic Orchestration - A Novel Framework for Stabilizing Mixed-Traffic Dynamics

2026-01-0099To be published on 04/07/2026

The recent rise in traffic flow instability and fatal accidents has become a central concern for transportation researchers and policy makers. Hansa Tek Netics (HTN) observes that technology-enabled vehicles - equipped with Advanced Driver Assistance Systems (ADAS) and Adaptive Cruise Control (ACC) - exhibit driving dynamics that diverge from those of human-driven vehicles. This divergence creates interaction conflicts that may amplify disturbances in mixed traffic, thereby contributing to the traffic’s metastability on freeways. To investigate this hypothesis, we developed a flow-centric analytical framework and analyzed the metastability phenomenon. Using both simulation and field observations, we examined how mismatched control philosophies between human and automated vehicles propagate disturbances across traffic streams. Results show that even small differences in dynamics cause positive feedback and trigger instabilities that spread nonlinearly through the flow. We observe that

Schlueter, Georg J.

Multi-material topology optimization using difference-based equivalent static load method

2026-01-0173To be published on 04/07/2026

Topology optimization (TO) has become a powerful tool for generating lightweight structural designs. TO has been widely applied to linear static problems, where analytical sensitivities are easy to obtain. However, crashworthiness design requires nonlinear dynamic analysis, for which analytical sensitivities are generally not available. To extend TO into crash problems, approximation methods such as the Equivalent Static Load (ESL) method have been developed. ESL replaces the nonlinear problem with a series of linear static subproblems, ensuring that the displacement fields match at certain time steps. These subproblems can then be efficiently solved using standard TO techniques. A key limitation of ESL is that it relies on the initial mesh for all subproblems, which reduces accuracy for highly nonlinear crash responses. To address this, Triller proposed the difference-based ESL (DiESL) method, which updates the mesh in each subproblem to the deformed configuration, therefore improving

Huang, Yuhao, Kim, Il Yong

Novel Steel Tubular Side Sill Reinforcement Design and Validation for Enhanced Crash Performance in EVs

2026-01-0478To be published on 04/07/2026

Increased use of Electrical vehicles (EVs) brings in unique structural design challenges particularly in Side Impact scenarios when the battery pack is near the sill region therefore elevating the possibility of Electrical Module penetration and triggering thermal runway event resulting from the crash. Thus, Electric Vehicles present unique structural design challenges. This study intends to evaluate a novel tubular structure design for side sill reinforcement and its performance benefits over a traditional aluminum side sill reinforcement currently commonly utilized for battery protection in EV vehicles body components. The proposed Steel side sill design mainly focuses on structural rigidity and improved load transfer during side pole impact crash cases and address manufacturing complexity and cost reduction opportunity. Multiple iterations for Steel side sill reinforcement design were carried out using finite element analysis with software like LSDYNA Hyper works to propose optimal

Kusnoorkar, Harsha, Khutorsky, Alex, Penumetsa, Vivek, Koraddi, Basavaraj

Optimization of Active–Passive Integrated Evaluation Weighting for Pedestrian Protection

2026-01-0577To be published on 04/07/2026

Pedestrians, as the most vulnerable road users, largely determine the severity of traffic accidents through the extent of their injuries. Traditional vehicle safety evaluations have primarily emphasized passive safety. However, with the widespread implementation of active safety technologies such as Automatic Emergency Braking (AEB), passive-only assessments no longer adequately reflect a vehicle’s true pedestrian protection performance.This study employed finite element models of a sedan and an SUV to analyze changes in pedestrian head and lower limb injury metrics before and after AEB intervention, thereby quantifying the associated injury-mitigation benefits. The results show that AEB reduced the maximum head injury value (HIC15) by about 50%, lowering the proportion of severe head injuries from 0.217 to 0.118. Conversely, braking-induced pitch effects increased the proportions of severe femur and tibia bending moment injuries to 0.235 and 0.294, respectively, making them higher

shi, Xinxin, YE, BIN, Liu, Yu, Zhan, Zhenfei, Sun, Bowen, Zhao, yuanyi, zhu, lei

Effects of Child Anthropometry, Seatback Angle, Seat Rotation Angle, Seatbelt Force Limiting, and Collision Type on Injury Risk of Child Occupants in Highly Automated Vehicles

2026-01-0570To be published on 04/07/2026

This study aimed to evaluate the influence of child anthropometry, seat posture (recline and rotation), seatbelt force limiting, and frontal collision scenarios on the kinematic response and injury risk to children in highly automated vehicles. The TUST IBMs 6YO-O model was conducted the frontal collisions in sled tests. This simulation matrix includes five percentiles six-year-old occupants (P3, P25, P50, P75, and P97), three seatback angles (20°, 30°, and 45°), four seat rotation angles (0°, 90°, 180°, and 270°), three seatbelt force limiting (2.6 kN, 3.6 kN, and 4.6 kN), and three collision types. Injury risks were assessed including the child occupant's head, neck, chest/abdomen, and lumbar region in each simulation (n=540). The results indicate that the child anthropometry, the seatback angle, and the seat rotation angle have a significant influence on the motion responses. Statistically significant differences between all the groups within each independent variable category were

Wang, Yanxin, Zhao, Hongqian, Li, Haiyan, He, Lijuan, Cui, Shihai, Lv, Wenle

Use inertial sliding of reclined seat to enhance occupant retention under rear-end crash

2026-01-0563To be published on 04/07/2026

Smart cabin of autonomous vehicle may lead more passengers to recline their seat for comfort. However, reclined seat is disadvantageous for holding occupant in seat when vehicle is subjected to rear-end crash. Under severe rear-end crash and large reclining angle, the backward inertia could completely throw occupant out of seat. Or, even if occupant body can be restrained well by seatbelt, the occupant head could slide out of the head restraint area. Any of these situations may potentially cause severe injuries. To address this safety concern, we developed a sliding seat system designed to enhance occupant retention. Activated by impact inertia from rear-end collision, the system allows the seat sliding backward along its track in a controlled manner, and the sliding stroke is accompanied by a restraint force and absorbs some amount of kinetic energy during the sliding. Meanwhile, the backward sliding of seat, together with backward sliding of occupant, makes the ride-down process more

Dai, Rui, Zhou, Qing, Puyuan, Tan, Shen, Wenxuan

Research on Vehicle Lateral Stability Under Flow Impact During Wading

2026-01-0624To be published on 04/07/2026

The growing frequency of extreme rainfall events attributable to global climate change has heightened concerns regarding flood-related hazards to road traffic safety. Under wading conditions, vehicles become susceptible to lateral sliding, flotation, or rollover when exposed to lateral hydrodynamic impacts, jeopardizing both occupant safety and infrastructure integrity. Previous studies have primarily focused on longitudinal sliding instability—such as the critical flow velocity for vehicle motion initiation and buoyancy-related submersion depth—under forward or backward flow, employing theoretical analyses and flume experiments. However, research on the dynamic response of vehicles under lateral flow, the underlying mechanisms of lateral skidding, and multi-degree-of-freedom instability modes remains relatively limited. To address this gap, this study establishes a multi-body vehicle dynamics model for lateral flow conditions, incorporating lateral hydraulic forces and tire-road

Wei, Haoting, Tan, Gangfeng, Lang, Tao, Liu, chongjian, Tang, Jingning

Evaluating the Effects of Improper Positioning and Unbuckling of a Restraint System on a 10-year-old Child ATD in a Far Side Side-Impact Environment

2026-01-0562To be published on 04/07/2026

Five sled tests were performed with a Hybrid III 10-year-old child ATD positioned in the 2nd row left seat of a three row 2006 Sport Utility Vehicle. The sled buck was positioned and accelerated on a Hyge Sled to replicate an intersection side impact collision to the passenger (right) side of the Sport Utility Vehicle. 3 of the 5 tests were performed with a delta-V of 17 mph, with one test performed with a properly restrained ATD and two tests performed with improper restraint positioning. 2 of the 5 tests were performed with a delta-V of 24 mph, and both tests included improper restraint positioning effectively identical to the two 17 mph delta-V tests. The first scenario of improper restraint positioning involved moving the torso belt from the left shoulder, over the head, and onto the right shoulder. The second scenario involved the same belt re-positioning as the first scenario, but additionally disengaged the latch plate from the buckle, essentially creating a condition of seat

Luepke, Peter, Hewett, Natalie, Betts, Kevin, Van Arsdell, William, Weber, Paul, Stankewich, Charles, Miller, Gregory, Watson, Richard, Sochor, Mark

Determining the Deployment Threshold of Active Head Restraints Through Real World Crashes.

2026-01-0533To be published on 04/07/2026

Accident reconstructionists often face the challenge of working with limited information when analyzing a collision. For this reason, every piece of data can be valuable. In this study, we are examining whether the deployment of an active head restraint can provide meaningful insight into the severity of a crash. To do this, the authors will use the Crash Investigation Sampling System (CISS) to identify vehicles involved in collisions where investigators noted the presence of active head restraints and where airbag control module data was available. From these cases, the status of the driver and right-front passenger active head restraints will be determined using the provided photographs. By correlating deployment status with crash severity, this study will estimate the likelihood of active head restraint deployment at varying levels of collision severity.

Fix, Ryan, Rutledge, Bradley

Occupant and Seat Responses in Various Rear Impact Conditions: Focus on Head-to-Head Restraint Interactions

2026-01-0565To be published on 04/07/2026

Head restraint requirements and designs have evolved to minimize the delay in head support and reduce differential loading in the neck. As a result, they have become bigger, closer to the occupant’s head, and angled forward relative to the seat back. Head restraints have been found missing or detached in the field; they may be removed pre-crash due to occupant comfort issues, or post-crash for better accessibility during extrication. Additionally, although rare, head restraints may become detached in severe rear impacts due to occupant loading. To better understand occupant-to-head restraint dynamic interactions, nine rear sled tests were conducted. The test conditions were selected to represent worst case severe loading scenarios. An instrumented 50th Hybrid III ATD (Anthropomorphic Test Device) was lap-shoulder belted on a right-front seat. The neck was equipped with a bracket and lower neck load cell designed for rear impacts. Three series of sled tests were performed wherein the

PARENTEAU, CHANTAL, Burnett, Roger, Davidson, Russell

Inertial Pedal Displacement and Brake Switch Activation in Frontal Crash Events

2026-01-0541To be published on 04/07/2026

This paper presents research into the inertial displacement of brake pedals and the subsequent activation of brake light switches during crash events. In certain scenarios—such as multiple-impact crashes or with pre-impact interactions such as curb strikes or sideswipes—inertial forces alone may generate sufficient brake pedal movement to trigger the brake switch, activating the brake lights. Such signals may be recorded by an Event Data Recorder (EDR) or observed by witnesses and mistakenly interpreted as an indication of intentional driver braking. To investigate this phenomenon, HYGE sled tests were performed using brake pedal assemblies and associated components from a Toyota Tacoma pickup truck and a Cadillac DeVille passenger sedan. The assemblies were subjected to acceleration pulses simulating a frontal impact, with high-speed video used to capture brake pedal displacement and brake light activation. The tests demonstrated that inertial loading from a pulse with a delta-V

Duran, Amanda, Walker, James, Barnes, Daniel, Osterhout, Aaron, Clayton, Aidan

Speed Determination Using Audio of Dash Camera Video from Commercial Vehicle Tires Frequencies for Vehicle Accident Reconstruction

2026-01-0536To be published on 04/07/2026

Prior research has validated a reliable method for determining vehicle speed using audio recorded by cameras mounted in vehicles, specifically for rolling passenger vehicle tires. Passenger vehicle tires produce a frequency component directly correlated to vehicle speed when traveling on concrete roadways. However, prior research has not been conducted on audio for rolling commercial vehicle tires, which differ in construction from passenger vehicle tires and therefore produce audio signals on roadway surfaces that passenger vehicles tires did not when tested in the prior study. The current research concluded that commercial vehicle tires rolling on various roadway surfaces also generated a frequency that varied with vehicle speed. The purpose of this study was to outline, test, and confirm the source of the speed-dependent frequency and to develop a validated method for use in forensic applications. A modified version of the passenger vehicle tire equation from prior research was

Vega, Henry V., Cornetto, Anthony, Ngo, Long Justin, Hatab, Ziad, Hunter, Eric

Statistical Assessment of Pretensioner and Load Limiter Effects on the Large Omnidirectional Child ATD Response in Frontal Impacts

2026-01-0550To be published on 04/07/2026

Enhancing child occupant protection requires a clear understanding of how seatbelt restraint parameters influence crash injury metrics. Real-world vehicles mostly include pretensioner and load limiter technologies to mitigate injuries, but rear seat restraints often do not include these. The FMVSS 213 test bench closely represents current restraint systems but does not involve such active vehicle restraint features. This study explores the response of the Large Omnidirectional Child ATD to evaluate potential injury mitigation under FMVSS 213 frontal sled test conditions. A simulation-based full factorial design was implemented in LS-DYNA to vary pretensioner retraction, retractor load-limiting thresholds, and webbing payout, with injury measures including head acceleration, head excursion, chest compression, and abdominal pressure (APTS). Statistical evaluation using analysis of variance (ANOVA) and Tukey-Kramer post-hoc tests quantified main and interaction effects. Pretensioners

Khattak, Mohid, Bendig, Colleen, Louden, Allison, Noll, Scott

From algorithm to engineering judgment: navigating topology optimization's limits in crash applications

2026-01-0189To be published on 04/07/2026

The non-linear nature of crash applications has led to many designs being developed through extensive trial and error based on the intuitions of the design engineer, as such using topology optimization for crash applications can provide major improvements in cost, weight, and passenger safety. Topology optimization is known for creating stiff, lightweight structures, however its application to crash scenarios must be handled carefully. Compliance minimization, the most common optimization objective, can yield misleading designs that prioritize undesirable qualities when developing structures for crash applications. In this paper the design optimization process of a passenger seat assembly subject to both an enforced displacement phase into a crash deceleration phase is discussed Due to the conflicting nature of compliance minimization and enforced displacement, the design was split into two types of regions; sacrificial, which are regions manually designed to absorb the majority of the

Orr, Mathew, Shi, Yifan, Lee, Jake, Gray, Savannah, Park, Taeil, Wotten, Erik, LeFrancois, Richard, Huang, Yuhao, Patel, Anuj, Kim, Hansu, Burns, Nicholas, Jalayer, Shayan, Grant, Robert, Kok, Leo, Hansen, Eric, Kim, Il Yong

Designing an e-SUV to Meet Global Front Crash Safety Standards

2026-01-0580To be published on 04/07/2026

Vehicle crashworthiness has improved tremendously over the past 20 years with increasing scenarios being defined and assessed by governments and nonprofits every few years. Bodies such as NTHSA, IIHS and EuroNCAP created safety ratings to distinguish objectively which vehicles are the safest for consumers. In doing so, automotive OEMs must spend more resources and design additional crash safety features onto their vehicles, often making them heavier in the process. As a result, negatively impacting the driving range of an electric vehicle. At Lucid Motors, through a holistic and first-principles approach, CAE simulations were used to guide the design of the Lucid Gravity to pursue highest possible crash safety ratings and battery protection while minimizing weight on the vehicle structure. By keeping the weight low, the Lucid Gravity Grand Touring was able to achieve an estimated EPA-rated range of 450 miles, which is groundbreaking for a full size 3-row electric SUV. This paper

Ng, Meng

Jute-Polyester Trim as a Novel Vehicle Upper Interior Head Impact Safety Countermeasure

2026-01-0567To be published on 04/07/2026

A significant fraction of annual global human mortality is caused by severe head injuries resulting from vehicle crashes. In order to ensure upper interior head impact safety in vehicles, stiff upper body pillars are covered with plastic trims often along with internal countermeasures such as fin-type monolithic ribs. In the study being reported here, a consistent Computer-Aided Engineering (CAE) procedure employing explicit nonlinear finite element analysis has been demonstrated for predicting headform impact safety of a steel A-pillar component covered with a novel jute-polyester trim. Using simulation as mentioned combined judiciously with test data and physical reasoning, a number of jute-polyester trim configurations are considered by varying the number of jute plies, and packaging space between trim and A-pillar inner panel. Additionally, jute-polyester trims with internal ribs are considered. The current study reinforces the potential of a jute polymer composite as a vehicle

Karthika, M R, Deb, Anindya, Zhu, Feng

A Study on the Relationship between Impact Conditions and Head Injury Criterion (HIC) in Powered-Two-Wheeler to Car Crashes

2026-01-0571To be published on 04/07/2026

Road Traffic crash statistics highlight the importance of reducing fatalities among Powered-Two-Wheeler (PTW) riders, and suggest the necessity of a robust method to evaluate PTW crashworthiness performance. The objective of this study is to clarify the relationship between impact conditions and the Head Injury Criterion (HIC) to establish a fundamental basis for determining representative crash configurations for safety. A total of 1,272 PTW-front to car-side impact simulations were conducted by using production car and PTW models. HIC was used as a metric indicating likelihood of head injury. Velocities, impact angle, and impact locations were varied to create response surfaces. The surfaces were evaluated in terms of their accuracy in identifying the representative impact conditions. In addition, head trajectories were analyzed to clarify the kinematics until head impact. The Finite Element (FE) simulations produced the following findings. - The HIC distribution by Head Impact

Yanaoka, Toshiyuki, GUNJI, Yasuaki, Zulkipli, Zarir Hafiz, Matsushita, Tetsuya, Carroll, Jolyon, Puthan, Pradeep, Mohd Faudzi, Siti Atiqah, D-Wing, Kak, Miyazaki, Yusuke

A Comprehensive Review of System Risk in Automotive Crash Safety

2026-01-0557To be published on 04/07/2026

Occupant protection has been at the forefront of risk evaluation regarding vehicle crashworthiness design. However, the vehicle is a member of a larger transportation system with varied stakeholders. This paper identifies an opportunity for assessing risk in a crash event through emerging safety science paradigms. Conventional Safety I and Safety II frameworks handle well-defined hazards but falter with uncertainty, variability, and emergent behaviors in real crashes. A comprehensive literature review was performed spanning standards, regulatory guidance, safety science, and peer-reviewed research to situate automotive crash safety risk within the Safety III paradigms. The review addresses two questions: (1) How is “risk” defined across the crash safety literature and adjacent safety science domains? and (2) What limitations arise from these definitions in practice? Findings show a dominant probabilistic framing alongside a minority of systems-oriented interpretations, with substantial

Rye, Patrick J.

Pre-Crash Scenario Analysis and Generation for Integrated Safety System Virtual Testing with Real Accident Data

2026-01-0062To be published on 04/07/2026

Integrated active and passive safety protection systems have made substantial contributions to reducing traffic accidents and mitigating human injuries. However, assessing such systems through vehicle collision tests is limited, as this approach can not cover the wide range of accident scenarios. To address this gap, identifying and generating representative pre-crash scenarios from real-world accidents provides key boundary conditions for the set up of virtual test scenarios. In this study, we used the Future Mobile Traffic Accident Scenario Study (FASS) dataset to reconstruct 112 two-wheeler accidents. For each case, we extracted pre-crash dynamic information, static attributes, and environmental context. An auto-encoder was employed to encode high-dimensional features of scenarios, and K-means clustering was applied to categorize the accidents into eight representative pre-crash scenarios. For each scenario, we examined the motion states of participants and further compared the

Wang, Guojie, Gao, Xin, Liu, Siyuan, Liu, Jiaxin, Li, Quan, shi, liangliang, Nie, Bingbing

Real-time Detection of Vehicle Drivers’ Distractions using YOLOv11

2026-01-0048To be published on 04/07/2026

Distracted driving is one of the main causes of traffic accidents and poses serious threats to safety of drivers, other road users and public property. Existing methods for detecting distracted driving often suffer from low detection accuracy, poor real-time performance, and high computational demand. This paper proposes a distracted driving behavior detection algorithm based on the latest YOLOv11 object detection model. The YOLOv11's is exhibits enhanced feature extraction capabilities and lightweight network design, which could identify distracted driving behaviors in a highly efficient manner. The study focusses on many different scenarios, such as phone usage, drinking and smoking while maintaining detection accuracy, by aligning with realistic driving scenarios, so as to facilitate development of a more suitable for in-vehicle driver monitoring systems. This study is expected to contribute towards enhanced road traffic safety through efficient detection of distracted driving

Ma, Bao Bao, Taghavifar, Hamid, Fu, Zhijun, Rakheja, Subhash, Karangwa, Jules

The Effects of Collision-Related Power Loss on Toyota Safety Sense 3.0 Event Data

2026-01-0548To be published on 04/07/2026

Toyota vehicles equipped with Toyota Safety Sense (TSS) can record detailed information surrounding various driving events. Often, this data is employed in accident reconstruction to better understand the dynamics of a collision. TSS data is comprised of three main categories: Vehicle Control History (VCH), Freeze Frame Data (FFD), and image records. During an event, it is possible that a vehicle undergoes a catastrophic power loss from the damages sustained during the event. In this paper, the effects of a sudden power loss on the VCH, FFD, and images are studied. Events are triggered on a TSS 3.0 equipped vehicle by driving toward a stationary target. After system activation, a total power loss is induced, triggered on the instrument cluster “BRAKE” alert message, at various delays after activation. This testing studies various signals recorded across VCH, FFD and image data including vehicle speed, measured accelerations and time and date. This testing also compares the acceleration

Getz, Charles, Yeakley, Adam, DiSogra, Matthew

Comparative Analysis of Rear Collision Prevention Systems

2026-01-0535To be published on 04/07/2026

Rear Collision Warning (RCW) and Rear Emergency Braking (REB) are key Advanced Driver Assistance Systems (ADAS) designed to prevent collisions with Vulnerable Road Users (VRUs) when a vehicle is reversing. These systems typically rely on a combination of radar, ultrasonic, and camera sensors. This study provides a comparative evaluation of Rear Collision Prevention systems across different vehicle manufacturers. Testing was performed on the 2022 Cadillac Escalade, 2017 Subaru Outback, and 2021 Ford F-150, using both static and moving pedestrian targets. Data collection was carried out with a VBOX data acquisition system, focusing on time-to-collision (TTC) as the primary performance metric. The analysis highlights variations in system effectiveness and provides a brief overview of OEMs' approach to pedestrian safety.

Harrington, Shawn, Takbhate, Shubham Ramraja, Nagarajan, Sundar Raman

Vault-Induced Pitchover Crash Testing of a Recreational Off-Highway Vehicle (ROV)

2026-01-0546To be published on 04/07/2026

VVehicle pitchover crashes can result in very severe accelerations and forces. Literature and test data available on pitchover crashes is sparse. This paper presents the results of a full-scale pitchover/rollover crash test using an instrumented vehicle in a controlled and documented off-road environment. The test vehicle was driven to the launch point by an off-board operator using remote steering and throttle controls. The test vehicle then experienced an airborne phase during which forward pitching occurred, followed by a front-to-ground impact which induced additional pitchover motion. Then, following the initial front and rear impacts, the vehicle transitioned from a pitchover to rollover motion before coming to rest. The resulting vehicle motion, vehicle damage markings, and ground markings were documented with various slow motion and real time camera views. The test vehicle was instrumented with accelerometers, rotation rate sensors, and other sensors, the results of which

Warner, Mark, Warner, Wyatt, Swensen, Grant, Perl, Mark

Quantifying the Accuracy of Detecting Lateral Movement Onset for a Selection of Bicycle GPS Computers

2026-01-0531To be published on 04/07/2026

Bicycle computers and apps record, at minimum, positional data over time, and this data is commonly used in accident reconstruction to inform the behavior of the bicycle and rider prior to an incident in question. This positional data is primarily calculated using the Global Positioning System (GPS) and thus specific accuracy and precision is not well quantified. To improve this understanding when it comes to relative accuracy of lateral movements, a series of controlled tests were performed and recorded with several commercially available bicycle GPS computers and apps and compared against a RaceLogic VBox 3i ADAS with Real-Time Kinematic corrections from a RaceLogic Base Station. The testing consisted of 5 sets of 15 runs: 15 runs riding down the center of a lane, 15 making a 6 ft lateral left movement, 15 making 12 ft lateral left movements, 15 making 6 ft lateral right movements, and 15 making 12 ft lateral right movements. Each test run was ended with hard braking to a stop to

Sweet, David Michael, Bretting, Gerald, O'Brien, Nathan, Wilhelm, Christopher

Development of A Tire Blowout Experimental Platform for Dynamics and Control Validation

2026-01-0202To be published on 04/07/2026

Tires are critical to vehicle dynamics, transmitting traction, braking, and cornering forces to the road. A tire blowout, the sudden and rapid loss of inflation pressure due to puncture or structural failure, can cause severe instability, rollover, or collisions. Understanding vehicle response during blowout events is essential for developing robust safety systems and control strategies. Earlier developed simulation models are used to study and understand vehicle behavior during blowouts, but there is a lack of on-road testing platforms to validate these models experimentally. A custom-built blowout device integrated with a data acquisition system has been developed to address this gap. It consists of multiple solenoid valves mounted on the wheel surface and powered by a 12V supply. All valves are triggered at the same time using an RF remote, producing rapid and synchronized deflation. An Arduino-based actuation system is being developed for individual valve actuation and custom

KANTHALA, Maha Vishnu Vardhan Reddy, Krishnakumar, Ashwin, Lin, Wen-Chiao, Chen, Yan

High Biofidelity Modification of Thoracolumbar Structure in THOR model for Reclined Occupant

2026-01-0196To be published on 04/07/2026

With the rapid development of automated driving and the increasing adoption of zero-gravity seats, the crash safety of highly reclined occupants has become a critical issue. The current THOR model, designed for frontal impacts in the standard upright posture, shows limitations when applied directly for reclined occupants, including excessive thoracolumbar flexion stiffness and large backward pelvis rotation. In this study, we analyzed the thoracolumbar spine kinematics of the THUMS human body model, which had been reconstructed against post-mortem human subject (PMHS) tests. A two-segment fitting was used to “dummy-ize” the spinal flexion response, yielding a virtual rotation hinge located close to the thoracic hinge of the original THOR model. The hinge rotation angle exhibited a strong linear correlation with the flexion moment of the L1–T12 segment. Based on this relationship, angular stiffness derived from the fitting was applied to the thoracolumbar hinge of the dummy. Additional

Guo, Wencheng, Kuang, Gaoyuan, Shen, Wenxuan, Tan, Puyuan, Zhou, Qing

Collision Avoidance Effectiveness of an Automated Driving System Using a Human Driver Behavior Reference Model in Reconstructed Fatal Collisions

2026-01-0520To be published on 04/07/2026

Avoiding and mitigating any potential collision is dependent on (1) road user ability to avoid entering into a conflict, the (conflict avoidance effect), and (2) road user response should a conflict be entered, the (collision avoidance effect). This study examined the collision avoidance effect of an automated driving system (ADS) using a human behavior reference model. The reference model used in this study reflects the response time and evasive action (referred to as collision avoidance) of a human driver that is non-impaired, with eyes on the conflict (NIEON) - a consistently performing, always-attentive driver that does not exist in the human population. Notably, the NIEON model is a tool for evaluating collision avoidance only, as it inherits the pre-conflict behaviors (includes conflict avoidance) of the ADS that is being evaluated. Counterfactual simulations were run on responder collision scenarios based on reconstructions from a 10-year period of human fatal crashes from the

Scanlon, John M., Kusano, Kristofer D., Engstrom, Johan, Victor, Trent

Effective design method for lightweight suite of seats considering crashworthiness and cost

2026-01-0493To be published on 04/07/2026

This paper presents a methodology for designing and evaluating lightweight, crashworthy aircraft seats that meet 21g crash safety standards and injury criteria. Four seat classes—economy double, economy single, single premium, and business—were developed using a modular design strategy focused on part commonality (family of parts) and manufacturability. A shared family of structural components was implemented across all seat types, with dimensional modifications applied only, when necessary, due to differences in seat width or height. In such cases, the same material systems and design principles were used to ensure consistency and reduce manufacturing complexity. The designs were evaluated using finite element simulations to verify performance under aerospace crash conditions. Each seat configuration was validated against regulatory crashworthiness criteria and injury thresholds, including pelvic, lumbar, and femur compressive forces, as well as head injury criteria (HIC) values. The

Gray, Savannah, Orr, Mathew, Shi, Yifan, Park, Taeil, Lee, Jake, Wotten, Erik, LeFrancois, Richard, Huang, Yuhao, Patel, Anuj, Kim, Hansu, Burns, Nicholas, Jalayer, Shayan, Grant, Robert, Kok, Leo, Hansen, Eric, Kim, Il Yong

High Order Control Lyapunov Function - Control Barrier Function - Quadratic Programming Based Autonomous Driving Controller for Bicyclist Safety

2026-01-0034To be published on 04/07/2026

Ensuring the safety of vulnerable road users is a critical challenge in the development of advanced autonomous driving systems. Among vulnerable road users, bicyclists present unique characteristics that make their safety both critical and manageable. Compared to pedestrians, vehicles often travel at significantly higher relative speeds when interacting with bicyclists, yet bicyclist motion is generally more predictable and governed by clear traffic rules, offering opportunities for model-based control strategies. To address bicyclist safety in complex traffic environments, this study proposes a High-Order Control Lyapunov Function–High-Order Control Barrier Function–Quadratic Programming (HOCLF-HOCBF-QP) control framework. By using this approach, CLFs enforce system stability, ensuring the vehicle follows a desired trajectory, while CBFs define safety boundaries, preventing collisions between the ego-vehicle and other road users. The optimal control input is then obtained by solving a

Chen, Haochong, Cao, Xincheng, Guvenc, Levent, Aksun Guvenc, Bilin

Advanced Tire Looseness Identification through Algorithmic Gear Error Analysis and Probabilistic Assessment

2026-01-0590To be published on 04/07/2026

At present, tire failures directly affect road safety, and the number of incidents caused by them is gradually increasing. Examining tire looseness on time is vital for vehicle safety. Tire-related incidents not only put people in peril but also have a detrimental effect on the economy. Therefore, the goal of this research is to develop a new and effective method for identifying tire looseness. A novel gear error reduction approach, distinct from traditional methods, combines advanced computing and probabilistic analysis. This paper involves three key components: extracting looseness eigenvalues, calculating ring gear errors, and computing the tire loosen probabilities. Gear errors derived from the Kalman filter and adjusted for speed, eigenvalues were calculated, and a tire loosening probability analysis was performed. Real-car trials across speeds and roads confirm its accuracy and reliability. This technology can improve automotive safety and maintenance, reducing accidents, claims

Zhao, Gaoming, Zhang, Zhijie, Liu, Jianjian, Ma, Guangtao, Wang, Zhenfeng, Zhao, Binggen

Risk analysis of occupant injuries with different lower limb postures during vehicle frontal impact

2026-01-0572To be published on 04/07/2026

To investigate the biomechanical characteristics of injuries sustained by occupants with different lower limb postures during frontal impact, the human body finite element models- THUMS AM50 under standard sitting posture and sitting posutres with 100° calf bend, 90° calf bend, and crossed legs were analyzed in the frontal impact at 56 km/h. Injury biomechanical analysis demonstrates that the occupant under the sitting posture with crossed legs has the highest overall injure risk, e.g, the highest HIC (Head Injury Critirion) value, peak value of head accerelation, VC (Viscous Crterion) values, strain of the thracic organs, stress of pelvic cortical bone and knee ligments, and so on. In summary, different lower limb postures can affect the overall risk of occupant injury: the smaller the calf flexion angle and the more complex the leg posture, the higher the risk of overall injury. In the future study it is necessary to strengthen the protection of occupants in non-standard seating

Li, Dongqiang, jiang, Yejie, Tan, Chun, Li, Yanyan, HeQuan, Wu, Jiang, Binhui, Zhu, Feng

Reconstruction of Pedestrian-Vehicle Collisions Using 3D Skeletal Estimation from Vehicle-Mounted Camera Video

2026-01-0575To be published on 04/07/2026

Since 2009, pedestrian fatalities caused by traffic accidents in the United States have increased by 78%, exceeding 7,000 deaths annually. To reduce injuries, a deeper understanding of injury mechanisms based on real-world accident data is required. Recently, accident reconstruction techniques utilizing recorded video from vehicle-mounted cameras have gained increasing attention in accident analysis. However, injuries resulting from contact with the road surface are often occluded due to camera blind spots, hindering accurate capture. Additionally, the low frame rate of many vehicle-mounted cameras limits the ability to accurately analyze the detailed kinematics of pedestrian impacts. To address these limitations, this study proposes a reconstruction method that estimates pedestrian motion in occluded regions by matching observed behavior from vehicle-mounted camera recorded video with simulation results. First, to reconstruct three-dimensional pedestrian motion from vehicle-mounted

Onishi, Koji, Wang, Kewang, Uno, Eriko, Ichikawa, Koji, Tanase, Noboru, Ando, Takahiro

Modified Hybrid A* Collision-Free Path-Planning for Parking a Vehicle in Tight Spaces

2026-01-0046To be published on 04/07/2026

Parking a vehicle in tight spaces is a challenging task to perform due to the scarcity of feasible paths that are also collision-free. This paper presents a strategy to tackle this kind of maneuver with a modified Hybrid-A* path-planning algorithm that combines the feasibility guarantee inherent in the standard Hybrid A* algorithm with the addition of static obstacle collision avoidance. A kinematic single-track model is derived to describe the low-speed motion of the vehicle, which is subsequently used as the motion model in the Hybrid A* path-planning algorithm to generate feasible motion primitive branches. The model states are also used to reconstruct the vehicle centerline, which, in conjunction with an inflated binary occupancy map, facilitates static obstacle collision avoidance functions. Simulation study and animation are set up to test the efficacy of the approach, and the proposed algorithm proves to consistently provide kinematically feasible trajectories that are also

Cao, Xincheng, Chen, Haochong, Aksun Guvenc, Bilin, Guvenc, Levent

Collapse Strength and Crush Space Analysis in Lateral Side Pole Impact of an Electric Vehicle

2026-01-0472To be published on 04/07/2026

High Voltage Battery (HVB) protection in lateral pole impact is very important due to severe nature of the impact. Unlike frontal impacts, vehicles have limited range of space and capacity to absorb kinetic energy in lateral side impacts. Nowadays, computer aided engineering (CAE) using finite element analysis (FEA) is utilized routinely to simulate high-speed crash events of varied type, including side pole impact. These CAE applications focus on the analysis and design of HVB when the vehicle structure is well developed. CAE methods are time consuming and are not suited during the pre-program stage when the structure is only in a concept stage and not even a reasonable CAD is available/developed in any sense to use these methods. There is no analytical tool available to understand how to define the characteristics of the structure that surrounds and protects the HVB. The primary motive of this publication is to help with this aspect of vehicle planning/development. Needless to state

Alavandi, Bhimaraddi, Midoun, Djamal, Frank, Randy

Machine Learning based Meta-Analysis of IIHS Moderate Overlap Frontal Crash Test for Rear Seat Occupant Safety Performance

2026-01-0579To be published on 04/07/2026

A machine learning (ML)-based meta-analysis was conducted to evaluate rear seat occupant safety performance in the Insurance Institute for Highway Safety (IIHS) Moderate Overlap Frontal (MOF) 2.0 crash test. ML models were trained on historical IIHS crash test data to predict rear passenger injury metrics using vehicle architecture, restraint system characteristics, crash pulse parameters, and vehicle kinematics as input features. The models demonstrated high predictive accuracy and were subsequently used in a Sobol sensitivity analysis to identify critical design parameters influencing injury outcomes. The analysis revealed that rear passenger injury metrics were most sensitive to restraint system parameters. Specifically, crash pulse magnitude was the dominant factor for head injury metrics, pretensioner activation time for neck tension force, and lap belt force for the Neck Injury Criterion (Nij). For chest-related metrics—sternum deflection, dynamic belt position, and maximum belt

Lalwala, Mitesh, Kim, Wonhee, Furton, Lisa, Song, Jay

Revisiting Rear Seat Safety: Field Evaluations of Relative Injury Risk Across Seating Positions and the Integration of Advanced Rear Seat Belt Systems.

2026-01-0561To be published on 04/07/2026

Despite advances in automotive crash avoidance, occupant restraint systems remain crucial in protecting the motoring public. Following decades of improvement in occupant protection, including the development of features such as frontal airbags, collapsable steering columns, and seat belt pretensioners and load limiters for the front seat, the safety of rear seat occupants has recently undergone scrutiny. Studies evaluating rear seat occupant injury risk via field crash data have reported findings of reduced relative safety in the rear seating positions and alluded to rear seat advanced restraints, such as pretensioners and load limiters, as a potential solution. While the pursuit of certain novel technologies has historically improved automotive occupant outcomes, evaluation of these new systems in both controlled laboratory environments and field crashes is necessary to understand potential positive and negative effects of widespread introduction. This study expanded upon prior field

Rapp van Roden, Elizabeth Ann, Miller, Bruce, Pearson, Joseph, Williamson, James, Brown, Thomas

A study on the injury risk of occupant with different head and neck rotating positions

2026-01-0574To be published on 04/07/2026

Drivers obtain road information through head and neck rotation. In order to study the impact of head and neck rotation posture on occupant injury in frontal collision, this paper studies the biomechanical response of occupants with five different head and neck rotation posture under 56 km/h frontal collision based on THUMS human model. Firstly, the kinematic response and head center-of-mass acceleration curves of the dead body and THUMS were compared to verify the validity of the vehicle model. Then, THUMS was adjusted to the standard occupant pose and five different head and neck rotation poses of ±20° and ±40°, and frontal collision simulation was conducted for each of the five poses with or without airbags. The results show that with the increase of head and neck rotation Angle, the risk of neck injury increases while the risk of chest injury decreases. 4 ribs are broken under standard posture, and only 2 ribs are broken when the left rotation of head and neck is 40°. The neck Nij

Li, Dongqiang, jiang, Yejie, Li, Yanyan, Tan, Chun, Jiang, Binhui

Pre-Impact Seat Rotation for Mitigating Lumbar Injury in Flying Car Crash

2026-01-0558To be published on 04/07/2026

Flying cars have already been used in tourism, firefighting, and logistics, and might be soon used for short-distance commute. However, the lumbar spine injury risks in flying car crash accidents have raised safety concerns. This is because the crash load of a flying car is largely aligned with the orientation of the occupant’s spine. This study introduces a countermeasure of actively adjusting seat posture for mitigating lumbar injury in crash events. A flying car crash usually has a few seconds of warning time before collision to ground. The pre-impact warning time is enough to rotate the seat and occupant together using seat motors. Posteriorly rotating seat can alter the angle between the crash load and the spinal axis, thereby reducing lumbar injury risk. Using numerical simulations, the 30g deceleration pulse defined in SAE-AS-8049 was applied to seat of flying car. The THUMS (Total Human Model for Safety) human body model was used to model occupant, sitting in a typical vehicle

Zhuang, Ziao, Puyuan, Tan, Shen, Wenxuan, Zhou, Qing, Gu, Gongyao

A Study on Vehicle Cornering Stiffness Estimation Based on Recursive Least Squares Method

2026-01-0630To be published on 04/07/2026

This paper investigates a vehicle cornering stiffness estimation method based on recursive least squares (RLS), aiming to enhance automotive active control capabilities. Conventional parameter identification schemes reliant on onboard sensors are constrained by sensing range and cost limitations. This study explores an estimation algorithm utilizing generic motion signals, derives the theoretical relationship between yaw rate response and yaw stiffness, and designs an RLS approach for online identification of relevant model parameters. In a simulation environment, applying an ideal steering angle excitation demonstrated that the RLS algorithm converges within approximately one second and successfully estimates the cornering stiffness with an error of less than 5% relative to the set true value. Results indicate that under known vehicle basic parameters and ideal input conditions, the proposed algorithm can effectively complete cornering stiffness estimation. This work establishes an

Lang, Tao, Tan, Gangfeng, duan, xianqi, Shen, Leiming, Liang, Shuang

Evaluation of PAEB Performance of a GM vehicle using EDR and Ground Truth Data

2026-01-0054To be published on 04/07/2026

In order to determine the on-board EDR data recording characteristics of a GM vehicle, a 2023 GMC Sierra Denali was tested in several pedestrian Automatic Emergency Braking (P-AEB) scenarios. Using a variety of test tools, including the STRIDE robotic platform and its onboard data systems, a GPS/IMU installed in the vehicle, and several camera units, the vehicle was put into collision imminent scenarios in which the crash avoidance systems were actuated. The flags in the EDR data, the order in which EDR events were written, and the correlation between the EDR and data recorded by the aforementioned external acquisition systems were examined for each test case. Testing was done in both forward and reverse scenarios and at low speeds only. These results provide a picture of the current state of the additional data available in current EDRs installed on GM vehicles equipped with P-AEB capability, as well as an insight into the accuracy and meaning of that data which should prove

Bartholomew, Meredith, Arnett, Michael, Guenther, Dennis

Analysis of the biofidelity of aPLI under low-speed collision conditions

2026-01-0551To be published on 04/07/2026

Abstract: With the increasing popularity of automotive active safety systems, the probability of collisions between vehicles and pedestrians has gradually decreased. Among them, the AEB system, as an important part of active safety systems, can actively intervene to avoid collisions in advance. However, in actual road traffic conditions, there are still situations where the AEB system cannot completely avoid collision accidents, and the impact speed between pedestrians and vehicles may drop to below 40 kph. However, the aPLI legform impactor, which is widely used in pedestrian protection evaluations in various regions, has a standard impact speed of 40 kph in the test procedure. The response of the aPLI to low-speed collisions and the resulting pedestrian leg injuries is still unclear. Based on finite element simulation, this study compared the kinematic responses and injury responses of the aPLI impactor with human body models (THUMS and GHBMC) under 5 different speeds (20kph, 25kph

Sun, Bowen, YE, BIN, LONG, YONGCHENG, Zhan, Zhenfei, shi, Xinxin, jun, yin

Benchmarking Driver Responses in Head-On Conflicts: Toward an Objective Protocol for Human and AV Evaluation

2026-01-0534To be published on 04/07/2026

Head-on emergency conflicts present a unique challenge for evaluating driver and automated vehicle (AV) performance. Unlike most emergency scenarios that follow a direct stimulus–response sequence, head-on encounters are characterized by a stimulus–wait–response pattern in which time to contact (TTC) strongly shapes driver behavior. Drawing on naturalistic and simulator data, this study quantified human responses to head-on conflicts. When the opposing vehicle crossed the centerline with more than 2 seconds of TTC, drivers delayed braking until an average of 1.3 seconds (SD = 0.8) before impact, regardless of the timing of the intrusion. By contrast, when TTC was less than 2 seconds, braking was initiated only 0 to 1.0 second before impact. As a result, many drivers applied the brakes less than half a second before collision. These findings provide a meta-analytically grounded benchmark for comparing human behavior to AV decision-making processes and demonstrate the need for conflict

Muttart, Jeffrey, Dinakar, Swaroop, Maloney, Tim, Adikhari, Bikram, Gernhard-Macha, Suntasty

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