Virtual homologation 
       of an ALKS according 
       to UNECE R157
                        |
                         Co-authored by
                                                  White paper
       Abstract
       Proving that an automated driving risk is acceptable requires extensive investigation into the challenge 
       of handling real-world traffic. UNECE R157 is the first regulation to formalise the idea of virtualising major 
       parts of the validation and homologation process. This white paper discusses a recommended process 
       for the virtual homologation of an Automated Lane Keeping System (ALKS) by following the provisions in 
       UNECE R157, including test approaches to prove system safety.
         TÜV SÜD
      Contents
      INTRODUCTION                                    3
      PROVING SYSTEM SAFETY                           6
      RELIABILITY OF SIMULATION RESULTS               10
      CONCLUSION                                      14
      About TÜV SÜD expert
                 Christoph Miethaner
                 Test Methods Engineer for Highly Automated Driving at TÜV SÜD
                 Christoph is an automated driving specialist with four years of industry experience and 
                 participates in various committees that promote the advancement of these complex 
                 automotive technologies. He is a member of the openSCENARIO working committee which 
                 focuses on the virtual development, test and validation of driver assistance functions, 
                 automated and autonomous driving. He is also a member of the committee ISO/TC22/SC33/
                 WG09 for test scenarios of automated driving systems, and DIN NA 052-00-33-09 AK, 
                 which is the national mirror committee of ISO/TC22/SC33/WG09. He is a member of the 
                 Methods, Models and Effectiveness Calculation working committee at P.E.A.R.S (Prospective 
                 Effectiveness Assessment for Road Safety), and represents the international not-for-profit 
                 association CITA (international motor vehicle inspection committee) at UNECE VMAD 
                 (Informal Working Group on Validation Methods for Automated Driving at United Nations 
                 Economic Commission for Europe).
      About dSPACE expert
                 Jann-Eve Stavesand
                 Head of dSPACE Consulting
                 Jann-Eve supports customers worldwide to define test strategies for complex automotive 
                 systems, helping them to overcome the challenges of developing safety-critical systems. 
                 He is a specialist in testing and quality assurance of complex automotive software and 
                 systems, including their approval and homologation. He sits on various standards committees 
                 in Germany and was involved in the development of ISO 26262:2018 - "Road vehicles – 
                 Functional safety", focusing on the software and processes elements. He is also involved 
                 with the standardisation of Safety of the Intended Functionality (SOTIF). 
        2                  Virtual homologation of an ALKS according to UNECE R157 | TÜV SÜD
                Introduction
                The high complexity of an automated         Proving that a risk is acceptable          According to these guidelines, 
                driving task has prompted the idea          requires extensive investigation into      simulation plays a crucial role for 
                of virtualising major parts of the          the challenge of handling real-world       safety argumentation. Validating 
                validation and homologation                 traffic. Currently, the prevailing         certain safety measures by simulation 
                process. UNECE regulation R157,             opinion among experts is that this task  means that it must also be proven 
                for the approval of vehicles with           can only be performed on a virtual         why the results of the simulation are 
                ALKS, is the first regulation to            basis. Therefore, several types of         reliable. The section “Reliability of 
                formalise these ideas. The authors          testing are required (from simulation      simulation results” gives an overview 
                of UNECE R157 not only defined              to real-world tests, see figure below).    of the different methods to achieve 
                a fixed set of test cases, but also         The following sections describe            trustworthiness of a virtual test setup. 
                augmented the prescribed set of             the virtual evaluation method used         In addition, we compared simulated 
                tests by making it a requirement to         to determine whether a risk is             traffic situations with equivalent 
                achieve higher-level principles, such       acceptable for an ALKS, as per the         real-world test drives to analyse the 
                as acceptable risk.                         UNECE R157 guidelines.                     accuracy of the simulation.
                                           CERTIFICATION AND SAFETY ARGUMENT PROCESS  
                                                          AND BASIS FOR VERIFICATION
                                                                                Argument for certification authorities  
                            Regulations                                           Argument for safety
                                   
                             Methods                            Verification results               Exploration of unknown
                                                                                                                                 Field observationT
                                                                     Selection                            Selection                      rustworthiness
                                KPI                                                           
                                                                                         Scenario 
                                                                                        catalogue
                                                                    Verification                          Validation
                        Scenario approach
                                                                      Test management framework (end-to-end)
                                                                     ODD
                                                                   Design                                 Test execution plan /  
                                                                                                              V&V Strategy
                                                                Risk Analysis
                     TÜV SÜD | Virtual homologation of an ALKS according to UNECE R157                                                    3
                Status quo – ALKS UNECE R157
                A key aspect of UNECE R157 that            which defines the same term as             Compared to the traditional 
                is unique to the regulatory and            “risk judged to be unacceptable in         homologation process, where 
                standardisation framework is the           a certain context according to valid       real-world test drives at the end 
                definition of a reasonable risk.           societal moral concepts,” UNECE            of the development process form 
                UNECE R157 Annex 4 Clause 2.16.            R157 redefines the threshold for an        the basis for homologation, UNECE 
                defines an unreasonable risk as            acceptable risk to a comparison that  R157 demands independent audits 
                “[...] the overall level of risk for       can be measured and argued to a            of relevant processes and their 
                the driver, vehicle occupants and          certain degree. This is a key enabler      implementation. Furthermore, 
                other road users which is increased        for the approval of vehicles with          several assessments are required 
                compared to a competently and              higher levels of automation, since         throughout the product lifecycle. For 
                carefully driven manual vehicle.”          it acknowledges the presences of a         details, refer to the figure below [1].
                Compared to existing sources, such         residual risk and provides guidance 
                as ISO 26262-1:2018 Clause 3.176,          on how this risk can be quantified.
                                         CONCEPT FOR CERTIFICATION – THE THREE PILLARS:  
                                                           PHASES OF TYPE APPROVAL
                                                                                         MAIN POINTS FOR CERTIFICATION
                                           Real-world                                    ■	 Overall impression of system 
                                            test drive                                      behaviour on public roads
                                                                                         ■	 Assessment of system's ability to 
                                                                                            cope with real-world traffic 
                                                                                         ■	 Validation of audit/assessment 
                                  Physical                                                  results with real-world behaviour
                                certification                                            ■	  Assessment of system behaviour in 
                                    tests                                                   fixed set of challenging cases
                                                                                         ■	  It is possible to reproduce situations 
                                                                                         ■	 Audit of development process and 
                                Audit                                                       V&V strategies
                                                                                         ■	  Assessment of safety concept 
                                                                                            (functional safety, safety of use)  
                   Assessment                                                               and measures taken 
                                                                                         ■	  Use of simulation results 
                                          Simulation                                     ■	  Measuring process maturity
                    4                                                 Virtual homologation of an ALKS according to UNECE R157 | TÜV SÜD