The 2019 standards distinguish between the skills that test drivers need for earlier- vs. later-stage prototype automated vehicles, said Barb Wendling, principal engineer of automated driving for Mercedes-Benz Research and Development North America.
Early-stage vehicles may be incomplete in terms of performance capabilities and thus require different skills from their drivers. Late-stage vehicles are less likely to require human intervention.
The standards also recommend having two drivers test the vehicle to help manage workload and ensure the testers aren't overloaded with tasks, Wendling said.
"They are supervising the automation, and if something goes wrong, they need to be ready at all times to intervene," Wendling said. "You have to be mindful of keeping their attention focused on supervising."
SAE also specified that it is helpful to limit the amount of time that test drivers spend on the road "because it is difficult for humans to remain attentive to a task that has very low workload demands for long periods of time."
Other organizations have weighed in on test-driving conditions before. Several automakers — among them Audi, BMW, Daimler, Fiat Chrysler Automobiles and Volkswagen — along with suppliers and technology firms developed the "Safety First for Automated Driving" white paper in July to create a framework for AV testing.
It noted the need to ensure "controllability" for the vehicle operator during testing.
"The automated driving system should continuously monitor the vehicle operator for possible distraction or mode confusion," the paper says.