The National Academies

NCHRP 20-102(32) [Final]

Safety Implications in a Mixed Vehicle Environment
[ NCHRP 20-102 (Impacts of Connected Vehicles and Automated Vehicles on State and Local Transportation Agencies--Task-Order Support) ]

  Project Data
Comments: NCHRP 17-91 and BTSCRP BTS-07 have been expanded in scope and budget to include this project


This project is combined with NCHRP Project 17-91 Assessing the Impacts of Automated Driving Systems (ADS) on the Future of Transportation Safety

C/AV technologies offer potentially transformative impacts on the transportation network and the traveling public. The adoption of these technologies, however, will take place over decades which will result in an interim mixed driving environment with regular, semi-automated, and highly-automated vehicles sharing the same roadway. This sustained mixed driving environment may raise currently un-anticipated safety issues that need to be considered as C/AVs enter the market. A 2017 report prepared for the Governors Highway Safety Association suggests that C/AV research has largely focused on the technology associated with deploying automated driving systems, whereas highway safety risks have largely been unconsidered. This report continues to say that C/AVs are expected to introduce new safety risks,
especially within the long transition period where mixed driving fleets occupy the transportation network and recommends the development of a "Traffic Safety Implications of Automated Vehicles" report to document these issues and encourage state officials to raise awareness of traffic safety concerns in C/AV planning efforts (https://www.ghsa.org/sites/default/files/2017-01/AV%202017%20-%20FINAL.pdf).

Following the recommendations of this report and numerous other calls to action, the purpose of this project is to raise awareness of these challenges through explicit identification of potential issues and develop a risk assessment based on a thorough review of findings from ongoing and completed research evaluating safety in a mixed fleet. This project may build upon the findings from:

  • NCHRP 20-102(27), Realistic Estimates of CAV Implementation Timing by focusing specifically on the safety challenges attributable to a mixed driving environment, and
  •  NCHRP 20-102(10), Cybersecurity Implications of CV/AV Technologies on State and Local Agencies.

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