This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Development and Application of a Collision Avoidance Capability Metric
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 14, 2020 by SAE International in United States
Annotation ability available
This paper describes the development and application of a newly developed metric for evaluating and quantifying the capability of a vehicle/controller (e.g., Automated Vehicle or human driver) to avoid collisions in nearly any potential scenario, including those involving multiple potential collision partners and roadside objects. At its core, this Collision Avoidance Capability (CAC) metric assesses the vehicle’s ability to avoid potential collisions at any point in time. It can also be evaluated at discrete points, or over time intervals. In addition, the CAC methodology potentially provides a real-time indication of courses of action that could be taken to avoid collisions.
The CAC calculation evaluates all possible courses of action within a vehicle’s performance limitations, including combinations of braking, accelerating and steering. Graphically, it uses the concept of a “friction ellipse”, which is commonly used in tire modeling and vehicle dynamics as a way of considering the interaction of braking and turning forces generated at the tire contact patches. When this concept is applied to the whole vehicle, and the actual or estimated maximum lateral and longitudinal accelerations of which the vehicle is capable are normalized, the ellipse becomes a circle that represents the boundaries of vehicle performance that can be utilized for driving, including evasive action. When a potential conflict with another object (e.g., another vehicle or pedestrian) is present, the CAC classifies operating areas within the circle as either successful (avoiding a collision) or not successful (resulting in a collision). The capability of a vehicle to avoid a collision is reflected in CAC, as CAC is larger when the range of possible successful avoidance maneuvers is larger and smaller when the range of possible successful avoidance maneuvers is smaller.
Development and derivation of the CAC are described, and various simulated and real-world test scenarios are described and evaluated.
CitationSilberling, J., Wells, P., Acharya, A., Kelly, J. et al., "Development and Application of a Collision Avoidance Capability Metric," SAE Technical Paper 2020-01-1207, 2020, https://doi.org/10.4271/2020-01-1207.
- National Highway Traffic Safety Administration , “Forward Collision Warning System Confirmation Test,” National Highway Traffic Safety Administration, February 2013.
- Insurance Institute for Highway Safety , “Pedestrian Autonomous Emergency Braking Test Protocol (Version II),” Insurance Institute for Highway Safety, February 2019.
- European New Car Assessment Programme , “Test Protocol - AEB Car-to-Car systems,” European New Car Assessment Programme. Version 3.0.1, February 2019.
- National Highway Traffic Safety Administration , “Development and Validation of Functional Definitions and Evaluation Procedures for Collision Warning/Avoidance Systems,” National Highway Traffic Safety Administration Technical Report, DOT HS 808 964, August 1999.
- van der Horst, A.R.A. “A Time-Based Analysis of Road User Behavior in Normal and Critical Encounters,” April 1990.
- Allen, B.L. et al. , “Analysis of Traffic Conflicts and Collisions,” McMaster University, Hamilton, Ontario, 1977.
- Shalev-Schwartz, S. et al. , “On a Formal Model of Safe and Scalable Self-driving Cars,” Mobileye, 2017.
- Barickman, F. , Instantaneous Safety Metric (National Highway Traffic Safety Administration, June 2019).
- Shelby, S.G. et al. , “Delta-V as a Measure of Traffic Conflict Severity,” September 2011.
- Oliveira, L. et al. , Driving Style: How Should an Automated Vehicle Behave? (University of Warwick, June 2019).
- Tesla Inc , “Q3 2018 Vehicle Safety Report,” https://www.tesla.com/blog/q3-2018-vehicle-safety-report, accessed January 8, 2020.