Drivers Reactions to Autopilot’s Disengagements, and Regulatory Implications for Semi-Autonomous Vehicles

Autonomous Vehicle (AV) technology is quickly expanding its market. Manufacturers are targeting different levels of autonomy, with semi-autonomous vehicles currently in the lead. In semi- autonomous vehicles, a human driver collaborates with the software that acts as “brain” of the vehicle and serves as back-up whenever the Autonomous Technology (AT) disengages after a failure. Current regulations for the State of California, a forerunner for the deployment of AV technology, only allow semi-autonomous collaborative vehicles to be deployed on public roads, with the requirement for the human driver to “monitor the safe operation of the vehicle at all times”, and that of being “capable of taking over immediate control in the event of an autonomous technology failure.”

In the safety-critical situation of an AT disengagement, it is important to ensure that the human driver has enough time to react and respond effectively to the request to control the vehicle. This study thus analyzes reaction times of human drivers placed in simulated AT disengagement scenarios.

The study here proposed can be broken down into two main phases: I) the examination of drivers’ responses to AT disengagements, with driver-in-the-loop simulation of AT failure scenarios and measurement of reaction times and study of situational awareness; II) inference and synthesis of the results in relation to existing AV policies, to better inform regulatory agencies, policy makers, and the general public of how the analyzed situations relate to drivers’ distraction/inattentiveness and translate in terms of safety of the semi-autonomous vehicle.

Video: Dr. Francesca Favaro discusses her current MTI research project and the work she does on autonomous systems



Mineta Consortium for Transportation Mobility
San José State University

Principal Investigator: 

Francesca Favaro, Ph.D.

PI Contact Information: 

Mineta Transportation Institute
San José State University
210 N. 4th St., 4th Floor
San José, CA 95112 

Funding Source(s) and Amounts Provided (by each agency or organization): 

U.S. Department of Transportation, Office of the Assistant Secretary for Research and Technology – $73,498.02 

Total Project Cost: 


Agency ID or Contract Number: 



September 2017 to June 2019

Project Number: