Unique signaling for autonomous vehicles to preserve user privacy

1. A method comprising:

receiving, by one or more computing devices, a first request for a vehicle, the request identifying user information for a user of a client computing device;

identifying, by the one or more computing devices, the client computing device based on the user information;

identifying, by the one or more computing devices, a location of the client computing device;

in response to the request, dispatching, by the one or more computing devices, a driverless vehicle to the location of the client device;

generating, by the one or more computing devices, signaling information based on a set of rules, the set of rules including:

a first rule that the signaling information does not identify, indirectly or directly, a user,

a second rule that the signaling information does not identify, indirectly or directly, the user information, and

a third rule that the signaling information was not previously generated for the user for a prior request for a vehicle;

sending, by the one or more computing devices, the location of the client computing device and the signaling information to the driverless vehicle for display to the user; and

sending, by the one or more computing devices, the signaling information to the client computing device for display to the user in order to identify the driverless vehicle to the user while preserving the user's privacy.

2. The method of claim 1 , wherein the request further includes a destination location and the set of rules further includes a fourth rule that the signaling information does not identify, directly or indirectly, the destination location, and the method further comprises:

providing the driverless vehicle with the destination location.

3. The method of claim 1 , wherein the set of rules further includes a fourth rule that the signaling information cannot already have been generated for another user for a third request for a vehicle.

4. The method of claim 1 , further comprising:

receiving, by the one or more computing devices, a notification from the driverless vehicle that the driverless vehicle has reached a threshold distance or time from the location of the client computing device, and

wherein the signaling information is sent to the driverless vehicle only after the notification is received.

5. The method of claim 4 , wherein the signaling information is sent to the client computing device only after the notification is received.

6. The method of claim 1 , wherein the set of rules includes a fourth rule that requires that the unique signal is to expire a specific amount of time after the driverless vehicle is expected to reach the location of the client computing device.

7. The method of claim 1 , wherein the request is received from a particular client computing device other than the client computing device and the method further comprises:

sending a request to the client computing device for the location of the client computing device, and

wherein identifying the location of the client computing device includes receiving the location of the client computing device in response to the request.

8. The method of claim 1 , wherein the set of rules further includes a fourth rule that the signaling information cannot have been generated for another user for a third request for a vehicle within a predetermined geographic area.

9. The method of claim 8 , wherein the fourth rule further includes a time limit such that after the time limit has expired, the signaling information can have been used for the another user for the third request within the geographic area.

10. A system comprising:

an electronic display positioned external to a vehicle;

one or more computing devices configured to:

receive, from one or more server computing devices, a message with dispatch instructions including a location;

maneuver the vehicle to the location;

receive, from the one or more server computing devices, signaling information;

determine when the vehicle reaches a particular location that is a threshold distance from the location; and

when the vehicle reaches the particular location, send a notification to one or more server computing devices;

receive the signaling information from the one or more server computing devices in response to the request; and

after receiving the signaling information, display the signaling information on the electronic display to identify the vehicle to a user.

11. The system of claim 10 , further comprising the vehicle, and wherein the one or more computing devices are incorporated into the vehicle.

12. The system of claim 10 , wherein the one or more computing devices are further configured to determine a route to the location, and the threshold distance is a distance in time along the route.

13. The system of claim 10 , wherein the one or more computing devices are further configured to determine a route to the location, and the threshold distance is a physical distance along the route.

14. The system of claim 10 , wherein the one or more computing devices are further configured to:

periodically receive an updated location; and

use the updated location to update the location such that the particular location is also updated.

15. The system of claim 10 , wherein the one or more computing devices are further configured to:

periodically receive an updated location; and

use the updated location to update the location such that the vehicle is maneuvered to the updated location.

16. The system of claim 10 , further comprising the one or more server computing devices.

17. The system of claim 16 , wherein the one or more server computing devices are configured to:

receive a request for a vehicle identifying the location and user information;

in response to the request, send the message to the one or more computing devices;

generate the signaling information based on a set of rules including a first rule that the signaling information does not identify, indirectly or directly, a user and a second rule that the signaling information does not identify, indirectly or directly, the user information; and

send the signaling information to the one or more computing devices.

18. The system of claim 17 , wherein the set of rules further includes a third rule that the signaling information cannot already have been generated for any user previously.

19. A non-transitory computer-readable storage medium on which computer readable instructions of a program are stored, the instructions, when executed by one or more processors, cause the one or more processors to perform a method, the method comprising:

in response to a request, dispatching a driverless vehicle to a location of a client device;

generating signaling information based on a set of rules, the set of rules including a first rule that the signaling information does not identify, indirectly or directly, a user and a second rule that the signaling information does not identify, indirectly or directly, user information;

receiving a notification from the driverless vehicle that the driverless vehicle has reached a threshold distance or time from the location of the client computing device;

in response to the notification, sending the location of the client computing device and the signaling information to the driverless vehicle for display to the user; and

sending the signaling information to the client computing device for display to the user.