Add Detroit to the cities where Amazon is testing its new battery-powered electric delivery van designed and built by Rivian.

Last week in Royal Oak, a suburb north of the Detroit city limits, an Amazon driver in a hand-built Rivian van, accompanied by a Rivian engineer, was delivering packages. It’s one of three vans currently being tested in the Detroit area.

Amazon plans to test the vans in 16 cities ahead of the official rollout, which starts next year with a production run of 10,000 vehicles. The vans have been spotted in San Francisco, Los Angeles, Denver and Tulsa, Okla.

The Rivian engineer accompanying the Amazon driver said the vans undergoing testing in the Detroit area were assembled at Rivian’s Plymouth, Mich., engineering and design center. The van looked production ready, with no obvious prototype or unfinished parts.

Amazon has invested more than $700 million in Rivian and plans to purchase 100,000 electric vans from the company by 2030.

While van deliveries appear to be on schedule, Rivian’s R1T electric pickup is late, frustrating customers who expected them to arrive late last year. The latest news from Rivian is that the first R1Ts will arrive in September.