After Phoenix and San Francisco, Los Angeles will be the next destination for the Waymo One robotaxi service.

In an announcement last week, Alphabet's self-driving car unit, Waymo, said its robotaxis will start driving across several L.A. districts over the coming months ahead of the start of the ride service. Waymo didn't say when the service will be open to the public but did say the service will operate around-the-clock.

Waymo has been testing self-driving cars on L.A. streets for years, including when the company was still known as the Google Self-Driving Car Project. In 2019, the company first started mapping L.A. streets for the Waymo One service.

Waymo hasn't provided a map of the areas Waymo One will cover, though the company mentioned popular L.A. spots like Downtown, Miracle Mile, Koreatown, Santa Monica, Westwood, West Hollywood, and Dodger Stadium.

L.A.'s streets will be the most challenging routes faced by the company yet, as Phoenix and San Francisco don't have the complex road structures and huge traffic volumes experienced in L.A. Specific challenges mentioned by Waymo include criss-crossing freeway ramps, narrow streets, blinding sunsets, and distracted drivers.

There's a lot to gain as the city has approximately 13 million residents and is the third largest location in the country for ride-hailing services, according to Waymo.

Waymo's self-driving system, known as the Waymo Driver, is rated at Level 4 on the SAE scale of self-driving capability, which means it can fully function on its own, though only within set conditions. Typically, Level 4 self-driving cars are limited to areas with sufficient map data, known as geo-fencing. The end goal is a Level 5 self-driving car, which will be able to function in all conditions expected of a human driver.

Unlike some rival self-driving systems, either in the works or already commercially available, robotaxis controlled by the Waymo Driver don't require NDAs, remote operators, or pre-defined pick-ups, according to Waymo.