Mercedes-Benz parent company Daimler and automotive supplier Bosch have started a trial self-driving service in the heart of Silicon Valley, specifically between downtown and west San José along the busy San Carlos/Stevens Creek corridor.

With more than a million residents, San José is the third biggest city in California, which makes it an ideal place to start the trial.

The trial is for an on-demand taxi service using self-driving car prototypes based on the Mercedes-Benz S-Class. It isn't a public trial, as only select users are able to hail a ride in one of the prototypes, which they can do via a dedicated app. And there's still a safety driver behind the wheel at all times.

The service is restricted via a defined pick-up location and geofenced route, which rates it as Level 4 on the SAE scale of self-driving capability. The end goal is a Level 5 system where a self-driving car can operate at the same capability as a human driver.

Daimler and Bosch self-driving car prototype in Silicon Valley

Daimler and Bosch self-driving car prototype in Silicon Valley

Daimler and Bosch have been jointly developing their self-driving system for several years. The researchers will use the trial to further fine-tune the system and gain insights into how self-driving cars can complement existing forms of transport.

Bosch handles the components specified during the development work, such as sensors, actuators, and control units. Daimler is tasked with integrating the required software and hardware into cars, as well as providing the prototypes and test facilities. Both firms have been testing self-driving cars on public roads since at least 2013.

Their goal is to develop a modular self-driving system, a so-called “automated driver,” that can be fitted to a variety of vehicle types.

Daimler is also working with BMW Group on self-driving cars. The two joined forces in February and in July said they aim to have cars with up to Level 4 self-driving capability on sale by 2024. The system will be restricted to highways and parking situations initially. Both automakers also plan to have a system able to handle urban areas and city centers, though timing for this feature is yet to be announced.