Google is hiring people in Arizona to sit in the front seat of its self-driving cars 'collecting data for our engineering team' on how the vehicles perform in the city's hot, dry and dusty roadways.

The California technology company has posted job ads looking to hire people in the Phoenix area who are willing to work six to eight hours a day, five days a week, for roughly $20 US an hour.

Applicants must be licensed drivers with clean records, but won't be called upon to take the wheel of four Lexus RX450h SUVs that have been equipped with Google's latest technology.

Rather, they will sit in the passenger seats of the vehicles while they drive around the city in real-world conditions, and at the end of each shift provide the company with "concise written and oral feedback to the engineering team," for how the cars performed under all conditions.

While it's unlikely to be needed, the humans selected must be able to take the wheel as circumstances warrant, because Google says its technology is not quite ready to be in control under all driving conditions. More testing in places like Phoenix could make that possible quicker, however.

One of Google's self-driving cars was pulled over recently for driving below the posted speed limit and impeding traffic in Mountain View California. (Aleksandr Milewski/Google)

Google's autonomous cars have clocked 2.4 million kilometres on U.S. roadways so far, but the company has identified the area around Phoenix as an ideal test market to take the next step.

That's because "Arizona is known as a place where research and development is welcome, innovation can thrive, and companies can set up roots," said Jennifer Haroon, head of business operations for the Google Self-Driving Car project.

"The Phoenix area has distinct desert conditions, which will help us better understand how our sensors and cars handle extreme temperatures and dust in the air."

The move toward autonomous vehicles got a shot in the arm last month when U.S. road regulator the National Highway Traffic Safety Administration declared that computer software could technically be considered a "driver" under U.S. law