A year out from announcing plans to partner on the development of self-driving cars, Toyota and Aurora Innovation have rolled out their first fleet of prototypes.

The prototypes are based on Toyota's Sienna minivan and have been deployed in Texas, where they are testing on both highways and suburban streets.

They are testing in the Dallas-Fort Worth area, where Aurora has been testing self-driving semi-trailer trucks since 2020. Some of the conditions the prototypes are faced with include U-turns, as well as high-speed mergers and lane changes. The prototypes can also react to irregularities such as vehicles on the shoulder, road construction, and poor weather.

Aurora has developed the self-driving system, known as the Aurora Driver, and Toyota has integrated this into its Sienna minivan. Members of the public aren't involved for the current phase of testing, and there's still an emergency driver behind the wheel at all times.

The Aurora Driver is rated at Level 4 on the SAE scale of self-driving capability. It can drive on its own for extended periods within specific conditions, the typical one being within a geofenced area. Level 5 is the ultimate goal, whereby a self-driving car is able to handle all of the same conditions as a human.

Aurora was established in 2016, with Chris Urmson, one of the early heads of the Google Self-Driving Car Project, now Waymo, among the co-founders. Another co-founder, Sterling Anderson, was in charge of development of Tesla’s Autopilot system in its early years.

Aurora's plan is to develop a reliable and robust self-driving system that can be integrated into taxi and trucking fleets. Aurora wants to offer a full service to companies operating the fleets, by covering the financing, insurance and maintenance aspects, as well as the actual self-driving technology.

Separately, Toyota is rolling out some self-driving capability in its showroom-bound models. The 2022 Toyota Mirai and 2022 Lexus LS are the first vehicles to offer some self-driving features grouped under the Toyota Teammate brand. These features are only ranked at Level 2 on the SAE scale, as they require constant monitoring from the driver. Level 3 is the first stage where a car can operate without supervision, with Honda already offering such a system in Japan and Mercedes-Benz close to offering one in Germany.