This report presents the results of one in a series of experiments that investigated driver performance in a generic Automated Highway System (AHS) configuration. The experiment examined how well drivers could take over a function(s) - steering alone, speed control alone or both - from the AHS when it was no longer able to perform that function(s). Results are reported.

This experiment is one in a series exploring human factors issues related to the Automated Highway System (AHS). The comfort level of the driver of the lead vehicle of a string of automated vehicles was determined (a) under normal AHS operating conditions, and (b) while a second vehicle was joining the string as the new lead vehicle. The experiment was conducted in the Iowa Driving Simulator. A generic AHS configuration was used--the left lane was reserved for automated vehicles, the center and right lanes contained unautomated vehicles, the center lane was not a dedicated transition lane, there were no barriers between the automated and unautomated lanes. Sixty drivers participated in the experiment--half male, half female; half between the ages of 25 and 34 years, half 65 or older.

Experts address some of the main issues and uncertainties associated with the design and deployment of Automated Highway Systems (AHS). They discuss new AHS concepts, technology, and benefits, as well as institutional, environmental, and social issues - concerns that will affect dramatically the operation of the current highway system from both the vehicle and infrastructure points of view.