Google continues to tap new testing locations for its self-driving cars, with the metropolitan area of Phoenix, Arizona picked as the next spot, reports Reuters. Jennifer Haroon, head of business operations for Google's autonomous vehicles said that Arizona was attractive not just as a place where tech research is welcome, but also because it provides "distinct desert conditions" to test the cars in different environments. "[This] will help us better understand how our sensors and cars handle extreme temperatures and dust in the air," said Haroon.

Google is also testing in Kirkland, Washington, for its rainy conditions

Testing self-driving cars in challenging conditions is essential for ensuring their safe operation. Google's autonomous vehicles have driven some 1.5 million miles in total, but mostly in relatively easy territory. Earlier this year, the company added the city of Kirkland as its third testing location with similar aims in mind. Although in that case, the Washington state location was selected for its wet, rainy conditions and numerous hills.

In February, one of Google's self-driving cars sideswiped a bus in an incident that the company admitted partial responsibility for. Google's test vehicles have been involved in a number of bumps and scrapes prior to this, but in all these cases the company's data showed that other drivers were at fault. Similarly, Google has reported a number of incidents when crashes might have happened if human test drivers had not intervened. The company continues to argue that if its cars can pass standardized federal safety tests, they should be classified as road-legal.