Assessing the Safety and Reliability of Autonomous Vehicles from Road Testing

Xingyu Zhao, Valentin Robu, David Flynn, Kizito Salako, Lorenzo Strigini

Research output: Chapter in Book/Report/Conference proceedingConference contribution

41 Citations (Scopus)
107 Downloads (Pure)


There is an urgent societal need to assess whether autonomous vehicles (AVs) are safe enough. From published quantitative safety and reliability assessments of AVs, we know that, given the goal of predicting very low rates of accidents, road testing alone requires infeasible numbers of miles to be driven. However, previous analyses do not consider any knowledge prior to road testing - knowledge which could bring substantial advantages if the AV design allows strong expectations of safety before road testing. We present the advantages of a new variant of Conservative Bayesian Inference (CBI), which uses prior knowledge while avoiding optimistic biases. We then study the trend of disengagements (take-overs by human drivers) by applying Software Reliability Growth Models (SRGMs) to data from Waymo's public road testing over 51 months, in view of the practice of software updates during this testing. Our approach is to not trust any specific SRGM, but to assess forecast accuracy and then improve forecasts. We show that, coupled with accuracy assessment and recalibration techniques, SRGMs could be a valuable test planning aid.
Original languageEnglish
Title of host publication30th IEEE International Symposium on Software Reliability Engineering (ISSRE 2019)
Number of pages11
ISBN (Electronic)9781728149820
Publication statusPublished - 10 Feb 2020
Event30th International Symposium on Software Reliability Engineering 2019 - Berlin, Germany
Duration: 28 Oct 201931 Oct 2019


Conference30th International Symposium on Software Reliability Engineering 2019
Abbreviated titleISSRE 2019


  • Autonomous vehicles
  • software reliability
  • Bayesian inference
  • safety-critical systems
  • reliability claims
  • Statistical analysis
  • Autonomous systems
  • software reliability growth model
  • ultra-high reliability


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