Detecting and responding to tailgaters

• US 8,818,682 B1
• Filed: 12/04/2013
• Issued: 08/26/2014
• Est. Priority Date: 07/24/2013
• Status: Active Grant

• Current Assignee: Waymo LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Dolgov, Dmitri A., Nemec, Philip, Aula, Anne
• Primary Examiner(s): Marc, McDieunel
• Application Number:
  US14/096,613
• Time in Patent Office: 265 Days
• Field of Search: 701/1, 701/93, 701/301, 701/451, 340/435, 340/436, 340/467, 340/901, 340/903, 340/933, 340/426.16, 340/427, 180/167, 455/500
• US Class Current: 701/96
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2554/80 Spatial relation or speed relative to objects
• CPC Class Codes: B60W 2554/801 Lateral distance
• CPC Class Codes: B60W 2554/802 Longitudinal distance
• CPC Class Codes: B60W 2754/30 Longitudinal distance
• CPC Class Codes: B60W 30/16 Control of distance between vehicles, e.g. keeping a distance to preceding vehicle
• CPC Class Codes: B60W 60/0016 of the vehicle or its occupants
• CPC Class Codes: B62D 15/025 Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation B62D1/28 takes precedence
• CPC Class Codes: B62D 15/0255 Automatic changing of lane, e.g. for passing another vehicle
• CPC Class Codes: G05D 1/00 Control of position, course, altitude or attitude of land, water, air or space vehicles, e.g. using automatic pilots drive control systems specially adapted for autonomous road vehicles B60W60/00
• CPC Class Codes: G05D 1/0055 with safety arrangements
• CPC Class Codes: G05D 1/0287 involving a plurality of land vehicles, e.g. fleet or convoy travelling traffic control systems for road vehicles G08G1/00, particularly anticollision systems G08G1/16

Abstract

An autonomous vehicle detects a tailgating vehicle and uses various response mechanisms. For example, a vehicle is identified as a tailgater based on whether its characteristics meet a variable threshold. When the autonomous vehicle is traveling at slower speeds, the threshold is defined in distance. When the autonomous vehicle is traveling at faster speeds, the threshold is defined in time. The autonomous vehicle may respond to the tailgater by modifying its driving behavior. In one example, the autonomous vehicle adjusts a headway buffer (defined in time) from another vehicle in front of the autonomous vehicle. For example, if the tailgater is T seconds too close to the autonomous vehicle, the autonomous vehicle increases the headway buffer to the vehicle in front of it by some amount relative to T.

Claims

1. A method comprising:

detecting, by one or more processors associated with a first vehicle, a second vehicle driving behind the first vehicle and in a same lane as the first vehicle;

detecting, by the one or more processors, a third vehicle driving in front of the first vehicle and in the same lane as the first vehicle;

determining, by the one or more processors, whether the second vehicle is within a threshold tailgating distance of the first vehicle;

when the second vehicle is within the threshold tailgating distance, determining, by the one or more processors, a difference in distance between the threshold tailgating distance and a distance between the second vehicle and the first vehicle; and

adjusting, by the one or more processors, a distance between the first vehicle and the third vehicle based on the difference in distance.

2. The method of claim 1, wherein adjusting the distance between the first vehicle and the third vehicle further includes:

retrieving a minimum headway time defining a minimum driving time between the first vehicle and any vehicle immediately in front of the first vehicle;

determining an amount of time to travel the difference in distance; and

adjusting the minimum headway time based on the amount of time.

3. The method of claim 2, further comprising further adjusting the adjusted minimum headway time based on any changes to a current speed of the first vehicle.

4. The method of claim 2, further comprising further adjusting the adjusted the minimum headway time based on any changes to the difference in distance.

5. The method of claim 2, further comprising continuing to adjust the adjusted minimum headway time until the distance between the first vehicle and the tailgater is greater than or equal to the distance threshold.

6. The method of claim 1, further comprising, before determining whether the second vehicle is within a threshold tailgating distance of the first vehicle, selecting the threshold tailgating distance over a threshold tailgating time when a current speed of the first vehicle is less than a speed threshold.

7. The method of claim 6, further comprising:

when the current speed of the first vehicle is greater than a speed threshold, selecting the threshold tailgating time over the threshold tailgating distance;

determining a difference in distance between the first vehicle and the second vehicle;

determining an amount of time for the first vehicle to travel the difference in distance between the first vehicle and the second vehicle;

when the amount of time is greater than the threshold tailgating time, determining a difference in time between the time threshold and the amount of time; and

adjusting a distance between the first vehicle and the third vehicle based on the difference in time.

8. The method of claim 7, wherein adjusting the distance between the first vehicle and the third vehicle based on the difference in time includes:

retrieving a minimum headway time defining a minimum driving time between the first vehicle and any vehicle immediately in front of the first vehicle;

adjusting the minimum headway time based on the difference in time.

9. The method of claim 1, further comprising determining the threshold tailgating distance using a function of a distance threshold component, a time threshold component, and a current speed of the vehicle.

10. A method comprising:

detecting, by one or more processors associated with a first vehicle, a second vehicle driving behind the first vehicle and in a same lane as the first vehicle;

detecting, by one or more processors, a third vehicle driving in front of the first vehicle and in the same lane as the first vehicle;

determining, by the one or more processors, a difference in distance between the first vehicle and the second distance;

determining, by the one or more processors, an amount of time for traveling the difference in distance;

when the amount of time is greater than a tailgating threshold time, determining, by the one or more processors, a difference in time between the time threshold and the amount of time; and

adjusting, by the one or more processors, a distance between the first vehicle and the third vehicle based on the difference in time.

11. The method of claim 10, wherein adjusting the distance between the first vehicle and the third vehicle further includes:

retrieving a minimum headway time defining a minimum driving time between the first vehicle and any vehicle immediately in front of the first vehicle; and

adjusting the minimum headway time based on the difference in time.

12. The method of claim 11, further comprising further adjusting the adjusted minimum headway time based on any changes to the current speed of the first vehicle.

13. The method of claim 11, further comprising further adjusting the adjusted the minimum headway time based on any changes to the difference.

14. The method of claim 11, further comprising continuing to adjust the minimum headway time until the amount of time is greater than or equal to the time threshold.

15. The method of claim 10, further comprising selecting the threshold tailgating time over a threshold tailgating distance when a current speed of the first vehicle is greater than a speed threshold.

16. The method of claim 15, further comprising:

when the current speed of the first vehicle is less than the speed threshold, selecting the threshold tailgating distance over the threshold tailgating time;

using the threshold tailgating time to determine whether the second vehicle is currently tailgating; and

when the second vehicle is currently tailgating adjusting the distance between the first vehicle and the third vehicle.

17. The method of claim 16, wherein adjusting the distance between the first vehicle and the third vehicle includes:

retrieving a minimum headway time defining a minimum driving time between the first vehicle and any vehicle immediately in front of the first vehicle;

adjusting the minimum headway time based on the determination that the second vehicle is currently tailgating.

18. A method comprising:

detecting, by one or more processors associated with a first vehicle, a second vehicle driving behind the first vehicle and in a same lane as the first vehicle;

detecting, by the one or more processors, a third vehicle driving in front of the first vehicle and in the same lane as the first vehicle;

selecting, by the one or more processors, between a threshold tailgating time and a threshold tailgating distance based on a current speed of the vehicle;

using, by the one or more processors, the selected threshold to determine when the second vehicle is tailgating;

when the second vehicle is tailgating, adjusting a minimum threshold time defining a minimum driving time between the first vehicle and any vehicle immediately in front of the first vehicle;

using, by the one or more processors, the adjusted minimum threshold time to determine a distance between the first vehicle and the third vehicle; and

controlling the first vehicle based on the distance.

19. The method of claim 18, further comprising further adjusting the minimum headway time based on any changes to the current speed of the first vehicle.

20. The method of claim 18, further comprising further adjusting the adjusted minimum headway time based on any changes to the difference.