We’ve reached a new milestone in the long road to getting AI-based self-driving systems to be truly autonomous.

Daimler and Bosch have now received approval from German regulators to run their automated driverless parking function without a human safety driver behind the wheel — making this the world’s first fully automated driverless SAE Level 4 parking function to be officially approved for everyday use. The nod comes four years after the companies started working together on the technology.

“This decision by the authorities shows that innovations like automated valet parking are possible in Germany first,” Bosch board member Dr. Markus Heyn said in a statement. “Driverless driving and parking are important building blocks for tomorrow’s mobility. The automated parking system shows just how far we have already progressed along this development path.”

Level 4 is a designation by SAE that means the vehicle can handle all aspects of driving in certain conditions without human intervention. Up to now, there have been other Level 4 trials in the works, but all of them have involved people behind the wheel as a back-up.

Bosch, one of the largest automotive tech and hardware suppliers in the world, handles the infrastructure piece of the automated parking function, which works in concert with Daimler’s vehicle tech on its Mercedes-Benz vehicles. Users access the autonomous valet service via a smartphone app.

Bosch and Daimler started developing fully automated driverless parking in 2015. That initial partnership included car2go, the car-sharing unit of Daimler. The companies debuted the so-called automated valet parking function in 2017 at the parking garage of the Mercedes-Benz Museum. The following year, and after intensive testing, museum visitors were able to test the automated parking service with one important caveat: a human safety driver was always behind the wheel.

Visitors were able to reserve vehicles from the facility using a smartphone app. Their vehicle would arrive autonomously to a designated pick-up spot in the parking garage. Once visitors were through with the vehicle, they could deliver it to the drop-off zone. The vehicle would then drive itself to its assigned parking spot, guided by the garage’s infrastructure and onboard sensors.

The pilot program was rather narrow in scope and restricted by the inclusion of a safety driver. But it served an important purpose for Bosch, Daimler and even other companies hoping to deploy automated driving functions in Germany.

Germany doesn’t have an official approval process for automated driving functions without a human driver. From the outset, Bosch and Daimler included authorities from Stuttgart and the state of Baden-Württemberg’s transportation ministry along with with experts from the German certification authority TÜV Rheinland.

As one might expect, the group assessed the safety of Bosch and Daimler’s parking function. But the process also helped regulators come up with a guidelines for testing and approval criteria that can be applied beyond this pilot project in one parking garage in Stuttgart.

For instance, Bosch and Daimler tested lighting concepts on the vehicles pilot project. The companies used turquoise lighting to indicate that a vehicle was in automated driving mode and informed passers-by and other road users that the vehicle is driving itself. The recently issued SAE standard 3134 reflects Bosch and Daimler’s insights on these lighting tests.

This isn’t the only Bosch-Daimler project in the works. The companies formed a partnership in 2017 to bring fully autonomous vehicles to urban roads “by the start of the next decade.” Last year, the companies announced plans to pilot a robotaxi service in San Jose, California.

The robotaxi trials, which will use automated Mercedes-Benz S Class vehicles, are supposed to begin in the second half of 2019 in a geofenced area in the San Carlos and Stevens Creek corridor between downtown and west San Jose. The pilot will use an on-demand ride-hailing service app operated by Daimler Mobility Services.

The rides will all be monitored by a safety driver.

Meanwhile, Bosch is building a $1.1 billion facility designed to produce semiconductors used in self-driving cars, smart homes and smart city infrastructure. The Dresden-based chip fab is set to start producing silicon commercially in 2021, and construction is supposed to be completed in 2019.