Using Technology Based Solution to Reduce Fatalities of Vulnerable Road User (VRU)
Authors:
Ibrahim Nassar (Electronics Team, Ozen Engineering)
Sri Konanur (Structures Team, Ozen Engineering)
Introduction to Vulnerable Road Users (VRU)
A vulnerable road user is a non motorist with a fatality analysis reporting system (FARS) person attribute code for pedestrian, bicyclist, other cyclist, and person on personal conveyance. They are at significantly higher risk of severe injury in a collision compared to occupants inside a car due to their lack of physical protection and greater exposure to impact forces during a crash. Technology based solutions such as Radar, Lidar, Sensors, AEB plays an important role in reducing the fatalities and injuries during an accident.
ANSYS Solution for Automotive Radar Simulation and Modeling
Radar is a key technology for autonomous vehicles and advanced driver assistance systems (ADAS). Simulation proves critical to the radar system design process and for ensuring performance when integrated on the vehicle through interactions with the surrounding, electrically large environment. With Ansys' proven electromagnetic simulation capabilities, engineers can rapidly analyze radar system performance in complex, dynamic scenarios and improve the accuracy of their response to potential hazards (Figure-1).
Figure-1. ANSYS HFSS Simulation of Installed Antennas on a car
Source: Ansys HFSS Comprehensive Radar Solutions for Autonomous Vehicles Youtube video
History of Occupant vs. Vulnerable Road User Safety in Transportation Systems
The proportion of vulnerable road user fatalities in traffic accident reduced from 28% in 1980 to 20% in 2000 as compared to the occupants inside the vehicle which increased from 72% to 80% during the same time period. The two main reasons for this are - 1. Lower number of distracted drivers (no cell phone, etc.) 2. Population in urban areas. However, since 2001 the proportion of fatalities in VRUs began to increase (20% to 34%), while the fatality of occupant inside the vehicle reduced (80% to 66%) as shown in Figure-1.
The main reasons for reduction in occupant fatalities inside the vehicle as automotive companies have developed technologies to protect the occupants inside the vehicle through structural design, safety features (airbags, auto braking, etc.), crash avoidance (rollover resistance, electronic stability control, etc) to meet regulatory standards and excellent consumer metric ratings.
With increasing urbanization and the rise in the number of large vehicles (SUV & Trucks) on the road, the need for enhanced protection of vulnerable road users (VRUs) has never been more critical. Addressing this issue requires a multifaceted approach that includes innovative vehicle design, implementation of advanced technology solutions, better infrastructure and increased awareness.
Governments and organizations worldwide are recognizing the importance of protecting VRUs and are investing in various initiatives to enhance their safety and create safer road environments for everyone.
The Growing Need for VRU Safety Solutions
In industrialized countries, including U.S.A road infrastructure and its environment have gradually developed in the last 20 years to meet the needs of growing traffic and mobility. The automotive manufacturers have implemented design changes as well as several safety features (safety cage design, airbag, seatbelt, crash avoidance, etc.) to reduce the injury and fatality of the occupant inside the vehicle as the regulatory requirements have been made compulsory. At the same time, the vulnerable road users which includes pedestrians and cyclists fatality rates in U.S.A have increased as compared to some of the European countries (Figure-2 & Figure-3).
Figure-2. Cyclic fatality rate comparison
Figure-3. Pedestrian fatality rate comparison
Factors affecting VRU fatalities
The contributing factors for higher vulnerable road user fatalities in USA are
- High average speed limits in USA
- Regulations that prioritize the convenience and speed of drivers at the expense of non-motorized transportation users
- Lower high-quality separated biking and walking infrastructure, good transit, and robust networks of automated enforcement
Key Features in ANSYS For Automotive Radar Integration
High-performance automotive radar design process includes antenna and array design, placement and integration, along with validation against simulated dynamic environments (Figure-4). Radar technology requires antennas to transmit and receive electromagnetic waves. Ideally, these antenna systems must concentrate energy on only the intended coverage zone that the sensor is observing. Obviously, the antennas must be carefully tuned to be efficient in radiating.
Figure-4 : Automotive Radar Design Process
High-frequency simulation with Ansys HFSS presents tremendous opportunities in the development of radar sensors. Ansys HFSS can be applied to the design of automotive radar sensors to:
- Rapidly explore new antennas and RF power distribution topologies
- Synthesize antennas and array systems for multichannel MIMO radar functions.
- Optimize RF power distribution, antenna subarray and array designs for maximum radiation efficiency, radiation beam shaping, array and subarray gain and sidelobe level control.
- Assess sensor packaging effects on the array and component subarrays, including environment-induced effects like water, ice, dust or mud coatings.
Where an antenna is placed significantly alters its radiation characteristics. The behavior of an antenna suspended in free space during testing can drastically change when it is placed near the dielectrics and conductors in the real world. This can reduce the effective detection range of the radar or introduce errors in determining the angle of arrival of targets. However, these simulations are usually electrically large and so require a lot of computational power and memory to solve. The Ansys HFSS Shooting and Bouncing Rays (SBR+) solver is an asymptotic, ray tracing electromagnetic solver that efficiently solves electrically large problems. HFSS SBR+ provides a high fidelity, physics-based simulation solution for solving electrically large problems in an efficient manner. Specifically, HFSS SBR+ computes installed antenna performance, extended near-field distributions, far-field radiation patterns, antenna-to-antenna coupling, radar cross section and radar returns from full-scale scenes. This enables engineers to :
- Assess the sensor placement (installation) effects on the sensor performance, and correct for sensor placement or interaction effects with the vehicle fascia, bumper or other vehicle structure.
- Simulate the installed sensor performance against “virtual world” traffic environments to test the quality of the sensor outputs for use with safety systems or AV control systems, many of which might otherwise be too dangerous for real-world testing.
Figure-5: Placement of radar antennas behind the emblem of a vehicle. The radome has a non-uniform thickness dielectric.
Vehicle Technological Solutions to protect VRU in traffic accidents
To reduce vulnerable road user fatalities along with the vehicle design changes, technological solution and high quality infrastructure implementation is necessary to reduce the fatalities in the USA. Here are some of the technological system and infrastructure changes that will reduce fatalities.
Technology and Driver Assistance Systems (Figure-6):
1. Automatic emergency braking (AEB): Systems that can detect pedestrians and automatically apply the brakes to avoid collisions.
2. Forward collision warning (FCW): Alerts drivers of potential collisions with pedestrians and cyclists, providing time to react.
3. Night vision systems: Improved night vision technology to better identify pedestrians and cyclists in low-light conditions.
4. Blind spot monitoring: Detects vehicles and pedestrians in blind spots, especially when turning.
Figure-6. Vehicle Technology Systems for VRU
Source : https://www.sema.org/news-media/enews/2023/35/customizing-confidence-sema-garage-release-white-paper-adas-equipped-truck
Technical Enablers to deliver VRU protection services (Figure-7):
1. Identifying Vulnerable Road User high risk zones: Drivers or automated vehicles get warnings when they
enter a high risk VRU static area ( schools, downtown, etc.) or dynamic area (school bus, mobile ice-cream vendor). Dedicated roadside infrastructure could play a vital role in providing warning messages to VRUs and vehicles as well.
2. : Interactive communications between VRU and vehicles: VRU using an interactive crossing application, whereby the VRU asks the vehicle for permission and the response is displayed to the VRU.
3. VRU safety messages and algorithms: Enabling PC5 technology in vehicles and smartphones. In this scenario, VRU devices send out safety messages (e.g. PSM, VAM) and vehicles send out safety
messages (e.g. CAM/DENM, BSM). Risk assessment is continually performed by
the most suitable unit (e.g. vehicle or infrastructure) and, if a collision is predicted,
warnings are then issued.
Figure-7. Technical Enablers between vehicles and VRU
Source: https://5gaa.org/publications/
Source: EuroNCAP - https://www.youtube.com/watch?v=279D7dVkBoo
Ansys Application for VRU ABE Analysis
Ansys LS-DYNA is used extensively across the automotive industry, with numerous case studies demonstrating its effectiveness in enhancing vehicle and occupant safety including VRU loadcase.
Since Ansys provides broad and deep capabilities for simulating autonomous vehicles and advanced driver assistance systems ( ADAS, 5G, Communication Technology, etc.). As most of the manufacturers and is going towards simulation to reduce testing cost during early development phase, Ansys products products can be utilized for simulations in area of connected mobility solutions, Autonomous and Electric vehicles. Ansys products will help in the areas of Connectivity and automation and offer great potential to reduce human errors and enhance the protection of VRUs.