The doors of Google’s self-driving vehicles are currently decorated with art work. There are sunsets, flowers and parks. But the warm nature scenes may eventually have competition for that real estate from an unlikely source — utilitarian traffic signage.

Google received a patent Tuesday detailing how a self-driving vehicle would determine if pedestrians were likely to cross a street, plan its next move accordingly, and then notify the pedestrians of its intent. Since the cars are being driven by a computer, a pedestrian can’t count on a hand signal or eye contact from a passenger to know a vehicle is waiting for them.

The patent describes using electronic screens mounted on the side of the vehicle — including potentially the roof, hood and rear of vehicle — to tell a pedestrians if it was safe to cross. The displays might show a stop sign, a traffic sign, or just text. The car might react by coming to a complete stop, slowing down and yielding, or maintaining its speed.

The patent also suggests some other options. A speaker on the outside of the vehicle might call out alerts, such as “coming through” or “safe to cross.” Perhaps most interesting is the potential use of a robotic hand and eyes to gesture at pedestrians and make them aware that the car “sees” them.

Sadly, no sketches of the robotic arm or eyes are included in the patent. Google initially filed for the patent in September 2012. The system is similar to one Nissan showed off last month, in which a screen on the dashboard shared messages with pedestrians.

On Tuesday, Google also received a patent for unlocking a driverless vehicle when approaching a passenger. The patent describes using Bluetooth or a local network to identify the close proximity of the user’s smartphone, and then unlocking the doors. Such a system would be essential if the technology was rolled out as an autonomous taxi fleet.