One year after announcing the purchase of 100,000 custom electric delivery vehicles, Amazon has begun testing its electric vans on delivery routes in the San Francisco Bay Area.

San Francisco is one of 16 cities where Amazon will be using these vehicles for customer deliveries in 2021. Amazon says the city was chosen because of its customers, unique terrain and climate, and that it plans to operate 10,000 of these vehicles as early as next year.

Designed and built in partnership with Rivian, Amazon’s first custom electric delivery vehicle was unveiled in October last year. The van is an all-electric delivery vehicle which can drive up to 150 miles on a single charge, and the company says it is optimized for safety and an enhanced driver experience. The vehicles are currently being driven by Amazon employees who are specially trained to operate them.

Deliveries will initially be conducted from Amazon’s delivery station in Richmond, California. Amazon says it plans to launch deliveries from other sites in the Bay Area soon.