Vehicle obstacle verification system

• US 7,532,109 B2
• Filed: 07/21/2006
• Issued: 05/12/2009
• Est. Priority Date: 08/02/2005
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Takahama, Taku, Kimura, Takeshi
• Primary Examiner(s): Pham; Toan N
• Assistant Examiner(s): McNally; Kerri L
• Application Number:
  US11/490,085
• Publication Number:
  US 20070030131A1
• Time in Patent Office: 1,026 Days
• Field of Search: 340/436
• US Class Current: 340/436
• CPC Class Codes: B60T 2201/02 Active or adaptive cruise control system; Distance control
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 2013/93185 Controlling the brakes
• CPC Class Codes: G01S 2013/932 using own vehicle data, e.g. ground speed, steering wheel direction
• CPC Class Codes: G08G 1/166 for active traffic, e.g. moving vehicles, pedestrians, bikes
• CPC Class Codes: G08G 1/167 Driving aids for lane monitoring, lane changing, e.g. blind spot detection

Abstract

A vehicle obstacle verification system and method is provided to improve the precision in which preceding objects are identified as being a potential obstacle to a host vehicle. The obstacle verification system (1, 2) uses at least two verification methods to make preliminary determinations as to whether a preceding object will become an obstacle in the future. The obstacle verification system (1, 2) also determines the precision of the verification results obtained with each of the verification methods. Additionally, the obstacle verification system (1, 2) calculates a verification result obtained using a verification method tailored to the traveling scene, the calculation being based on the verification results obtained using the plurality of verification methods, and makes a final determination as to whether the preceding object will become an obstacle based on the calculated verification result and the previously determined precisions.

Claims

1. An obstacle verification system comprising:

an object detecting section configured to detect a preceding object existing in front of a host vehicle;

a vehicle running state detecting section configured to output a running state detection result indicative of a vehicle running state;

a traveling scene determining section configured to determine a current traveling scene based on both a longitudinal relative velocity of the preceding object detected by the object detection section with respect to the host vehicle in a longitudinal direction of the host vehicle and a transverse relative velocity of the preceding object detected by the object detecting section with respect to the host vehicle in a widthwise direction of the host vehicle;

a preliminary obstacle verifying section configured to make a plurality of preliminary determinations as to whether the preceding object will become an obstacle using a plurality of verification methods, respectively, with each of the verification methods obtaining the preliminary determinations based on both the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a precision determining section configured to determine a degree of precision regarding each of the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods; and

a final obstacle verifying section configured to calculate a verification result based on the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods and based on the current traveling scene determined by the traveling scene determining section, and the final obstacle verifying section being further configured to make a final determination as to whether the preceding object will become an obstacle based on the verification result and the degrees of precision determined by the precision determining section for the preliminary determinations.

2. The obstacle verification system as recited in claim 1, wherein

the traveling scene determining section is further configured such that as the longitudinal relative velocity of the preceding object with respect to the host vehicle is smaller in a direction of the preceding object approaching the host vehicle along the longitudinal direction of the host vehicle and as an absolute value of the transverse relative velocity of the preceding object with respect to the host vehicle is larger in the widthwise direction of the host vehicle, then the traveling scene determining section determines that the current traveling scene is more likely a vehicle lane-change scene in which the host vehicle or another vehicle is changing lanes.

3. The obstacle verification system as recited in claim 1, wherein

the traveling scene determining section is further configured such that as the longitudinal relative velocity of the preceding object with respect to the host vehicle is larger in a direction of the preceding object approaching the host vehicle along the longitudinal direction of the host vehicle, then the traveling scene determining section determines that the current traveling scene is more likely an emergency scene requiring the host vehicle to perform an emergency avoidance measure.

4. The obstacle verification system as recited in claim 1, wherein

the preliminary obstacle verifying section is further configured such that one of the verification methods is a high accuracy method that involves predicting a host vehicle path based on the running state of the host vehicle detected by the vehicle running state detecting section and preliminarily determining if the preceding object will become an obstacle by comparing the host vehicle path that was predicted to a position of the preceding object detected by the object detecting section.

5. The obstacle verification system as recited in claim 4, wherein

the precision determining section is further configured to determine the degree of precision of the verification result obtained with the high accuracy method based on a detected lateral width of the preceding object.

6. The obstacle verification system as recited in claim 1, wherein

the preliminary obstacle verifying section is further configured such that one of the verification methods is a medium accuracy method that involves predicting a host vehicle path based on the running state of the host vehicle detected by the vehicle running state detecting section and preliminarily determining if the preceding object will become an obstacle by comparing the host vehicle path that was predicted to a hypothetical object position where the preceding object detected by the object detecting section can be assumed to be located after moving for a prescribed amount of time along a currently detected object path.

7. The obstacle verification system as recited in claim 6, wherein

the precision determining section is further configured to lower the degree of precision of the verification result obtained with the medium accuracy method as a distance between the host vehicle and the preceding object increases.

8. The obstacle verification system as recited in claim 6, wherein

the precision determining section is further configured to lower the degree of precision of the verification result obtained with the medium accuracy method as a temporal spacing between the host vehicle and the preceding object increases.

9. The obstacle verification system as recited in claim 6, further comprising:

a road component verifying section further configured to determine if the preceding object is a part of the road infrastructure,

the precision determining section being further configured to lower the degree of precision of the verification result obtained with the medium accuracy method when the preceding object is determined to be a road structure by the road component verifying section.

10. The obstacle verification system as recited in claim 6, wherein

the preliminary obstacle verifying section is further configured to assume that the temporal spacing between the host vehicle and the preceding object is the prescribed amount of time.

11. The obstacle verification system as recited in claim 1, wherein

the preliminary obstacle verifying section is further configured such that one of the verification methods is a high response method that involves preliminarily determining if the preceding object will become an obstacle based on a relative movement direction of the preceding object with respect to the host vehicle and a prescribed time value in which a movement direction of the preceding object is assumed to remain unchanged.

12. The obstacle verification system as recited in claim 1, wherein

the traveling scene determining section is further configured to determine a matching degree of each of a plurality prescribed traveling scenes with the current traveling scene based on the preceding object by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section.

13. A vehicle equipped with the obstacle verification system according to claim 1.

14. An obstacle verification system comprising:

an object detecting section configured to detect a preceding object existing in front of a host vehicle;

a vehicle running state detecting section configured to output a running state detection result indicative of a vehicle running state;

a traveling scene determining section configured to determine a current traveling scene based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a preliminary obstacle verifying section configured to make preliminary determinations as to whether the preceding object will become an obstacle using a plurality of verification methods based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a precision determining section configured to determine a degree of precision regarding each of the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods; and

a final obstacle verifying section configured to calculate a verification result based on the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods and based on the current traveling scene determined by the traveling scene determining section, and the final obstacle verifying section being further configured to make a final determination as to whether the preceding object will become an obstacle based on the verification result and the degrees of precision determined by the precision determining section for the preliminary determinations,

the traveling scene determining section being further configured such that as a longitudinal relative velocity of the preceding object with respect to the host vehicle is smaller in a direction of the preceding object approaching the host vehicle along a longitudinal direction of the host vehicle and as an absolute value of a transverse relative velocity of the preceding object with respect to the host vehicle is smaller in a widthwise direction of the host vehicle, then the traveling scene determining section determines that the current traveling scene is more likely a following scene in which the host vehicle is following a preceding vehicle.

15. An obstacle verification system comprising:

an object detecting section configured to detect a preceding object existing in front of a host vehicle;

a vehicle running state detecting section configured to output a running state detection result indicative of a vehicle running state;

a traveling scene determining section configured to determine a current traveling scene based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a preliminary obstacle verifying section configured to make preliminary determinations as to whether the preceding object will become an obstacle using a plurality of verification methods based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a precision determining section configured to determine a degree of precision regarding each of the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods; and

a final obstacle verifying section configured to calculate a verification result based on the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods and based on the current traveling scene determined by the traveling scene determining section, and the final obstacle verifying section being further configured to make a final determination as to whether the preceding object will become an obstacle based on the verification result and the degrees of precision determined by the precision determining section for the preliminary determinations,

the preliminary obstacle verifying section being further configured such that one of the verification methods is a medium accuracy method that involves predicting a host vehicle path based on the running state of the host vehicle detected by the vehicle running state detecting section and preliminarily determining if the preceding object will become an obstacle by comparing the host vehicle path that was predicted to a hypothetical object position where the preceding object detected by the object detecting section can be assumed to be located after moving for a prescribed amount of time along a currently detected object path, and

the precision determining section being further configured to raise the degree of precision of the verification result obtained with the medium accuracy method as a detected speed of the host vehicle detected by the vehicle running state detecting section increases.

16. An obstacle verification system comprising:

an object detecting section configured to detect a preceding object existing in front of a host vehicle;

a vehicle running state detecting section configured to output a running state detection result indicative of a vehicle running state;

a traveling scene determining section configured to determine a current traveling scene based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a preliminary obstacle verifying section configured to make preliminary determinations as to whether the preceding object will become an obstacle using a plurality of verification methods based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a precision determining section configured to determine a degree of precision regarding each of the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods; and

a final obstacle verifying section configured to calculate a verification result based on the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods and based on the current traveling scene determined by the traveling scene determining section, and the final obstacle verifying section being further configured to make a final determination as to whether the preceding object will become an obstacle based on the verification result and the degrees of precision determined by the precision determining section for the preliminary determinations,

the preliminary obstacle verifying section being further configured such that one of the verification methods is a high accuracy method that involves predicting a host vehicle path based on the running state of the host vehicle detected by the vehicle running state detecting section and preliminarily determining if the preceding object will become an obstacle by comparing the host vehicle path that was predicted to a position of the preceding object detected by the object detecting section,

the object detecting section having a detector configured to detect objects existing within a prescribed region in front of the host vehicle, and

the precision determining section being further configured to lower the degree of precision of the verification result obtained with the high accuracy method as the preceding object approaches an edge of the prescribed region in front of the host vehicle.

17. An obstacle verification system comprising:

an object detecting section configured to detect a preceding object existing in front of a host vehicle;

a vehicle running state detecting section configured to output a running state detection result indicative of a vehicle running state;

a traveling scene determining section configured to determine a current traveling scene based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a preliminary obstacle verifying section configured to make preliminary determinations as to whether the preceding object will become an obstacle using a plurality of verification methods based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a precision determining section configured to determine a degree of precision regarding each of the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods; and

a final obstacle verifying section configured to calculate a verification result based on the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods and based on the current traveling scene determined by the traveling scene determining section, and the final obstacle verifying section being further configured to make a final determination as to whether the preceding object will become an obstacle based on the verification result and the degrees of precision determined by the precision determining section for the preliminary determinations,

the preliminary obstacle verifying section being further configured such that one of the verification methods is a high response method that involves preliminarily determining if the preceding object will become an obstacle based on a relative movement direction of the preceding object with respect to the host vehicle and a prescribed time value in which a movement direction of the preceding object is assumed to remain unchanged,

the object detecting section being configured to detect objects existing within a prescribed region in front of the host vehicle, and

the precision determining section being further configured to raise the degree of precision of the verification result obtained with the high response method as the preceding object approaches the front of the host vehicle.

18. An obstacle verification system comprising:

an object detecting section configured to detect a preceding object existing in front of a host vehicle;

a vehicle running state detecting section configured to output a running state detection result indicative of a vehicle running state;

a traveling scene determining section configured to determine a current traveling scene based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a preliminary obstacle verifying section configured to make preliminary determinations as to whether the preceding object will become an obstacle using a plurality of verification methods based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a precision determining section configured to determine a degree of precision regarding each of the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods; and

a final obstacle verifying section configured to calculate a verification result based on the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods and based on the current traveling scene determined by the traveling scene determining section, and the final obstacle verifying section being further configured to make a final determination as to whether the preceding object will become an obstacle based on the verification result and the degrees of precision determined by the precision determining section for the preliminary determinations,

the preliminary obstacle verifying section being further configured such that one of the verification methods is a high response method that involves preliminarily determining if the preceding object will become an obstacle based on a relative movement direction of the preceding object with respect to the host vehicle and a prescribed time value in which a movement direction of the preceding object is assumed to remain unchanged, and

the precision determining section being further configured to lower the degree of precision of the verification result obtained with the high response method when the preceding object is determined to be a moving body.

19. An obstacle verification system comprising:

an object detecting section configured to detect a preceding object existing in front of a host vehicle;

a vehicle running state detecting section configured to output a running state detection result indicative of a vehicle running state;

a traveling scene determining section configured to determine a current traveling scene based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a preliminary obstacle verifying section configured to make preliminary determinations as to whether the preceding object will become an obstacle using a plurality of verification methods based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a precision determining section configured to determine a degree of precision regarding each of the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods; and

a final obstacle verifying section configured to calculate a verification result based on the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods and based on the current traveling scene determined by the traveling scene determining section, and the final obstacle verifying section being further configured to make a final determination as to whether the preceding object will become an obstacle based on the verification result and the degrees of precision determined by the precision determining section for the preliminary determinations,

the preliminary obstacle verifying section being further configured such that one of the verification methods is a high response method that involves preliminarily determining if the preceding object will become an obstacle based on a relative movement direction of the preceding object with respect to the host vehicle and a prescribed time value in which a movement direction of the preceding object is assumed to remain unchanged, and

the preliminary obstacle verifying section being further configured such that as a detected steering angular velocity of the host vehicle approaches zero, then the preliminary obstacle verifying section sets the prescribed amount of time to a longer period of time.

20. The obstacle verification system as recited in claim 19, wherein

the preliminary obstacle verifying section is further configured such that as an absolute value of a detected steering angle of the host vehicle becomes larger and a detected acceleration of the host vehicle becomes larger, then the preliminary obstacle verifying section sets the prescribed amount of time to shorter period of time.

21. An obstacle verification system comprising:

an object detecting section configured to detect a preceding object existing in front of a host vehicle;

a vehicle running state detecting section configured to output a running state detection result indicative of a vehicle running state;

a traveling scene determining section configured to determine a current traveling scene based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a preliminary obstacle verifying section configured to make preliminary determinations as to whether the preceding object will become an obstacle using a plurality of verification methods based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a precision determining section configured to determine a degree of precision regarding each of the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods; and

a final obstacle verifying section configured to calculate a verification result based on the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods and based on the current traveling scene determined by the traveling scene determining section, and the final obstacle verifying section being further configured to make a final determination as to whether the preceding object will become an obstacle based on the verification result and the degrees of precision determined by the precision determining section for the preliminary determinations,

the traveling scene determining section being further configured to determine a matching degree of each of at least two prescribed traveling scenes, which includes at least a following scene in which the host vehicle is following a preceding vehicle and another traveling scene other than the following scene, with the current traveling scene,

the preliminary obstacle verifying section being further configured to execute as the verification method at least a high accuracy method that involves predicting a host vehicle path of the host vehicle based on the running state of the host vehicle detected by the vehicle running state detecting section and preliminarily determining if the preceding object will become an obstacle by comparing the host vehicle path to a detected position of the preceding object detected by the object detecting section, and at least one other verification method other than the high accuracy method, and

the final obstacle verifying section being further configured to make the final determination as to if the preceding object will become an obstacle such that the final obstacle verifying section gives more weight to the preliminary determination obtained with the high accuracy method in making the final determination as the matching degree of the following scene determined by the traveling scene determining section becomes higher.

22. An obstacle verification system comprising:

an object detecting section configured to detect a preceding object existing in front of a host vehicle;

a vehicle running state detecting section configured to output a running state detection result indicative of a vehicle running state;

a traveling scene determining section configured to determine a current traveling scene based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a preliminary obstacle verifying section configured to make preliminary determinations as to whether the preceding object will become an obstacle using a plurality of verification methods based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a precision determining section configured to determine a degree of precision regarding each of the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods; and

a final obstacle verifying section configured to calculate a verification result based on the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods and based on the current traveling scene determined by the traveling scene determining section, and the final obstacle verifying section being further configured to make a final determination as to whether the preceding object will become an obstacle based on the verification result and the degrees of precision determined by the precision determining section for the preliminary determinations,

the traveling scene determining section being further configured to determine a matching degree of each of at least two prescribed traveling scenes, which includes at least a lane-change scene in which the host vehicle in which the system is employed or another vehicle is changing lanes and another traveling scene other than the lane-change scene,

the preliminary obstacle verifying section being further configured to execute as the verification method at least a medium accuracy method that involves predicting a host vehicle path of the host vehicle based on the running state of the host vehicle detected by the vehicle running state detecting section and preliminarily determining if the preceding object will become an obstacle by comparing the host vehicle path to a hypothetical position where the preceding object detected by the object detecting section will be assumed to be located after moving for a prescribed amount of time along a currently detected object path, and at least one other verification method other than the medium accuracy method, and

the final obstacle verifying section being further configured to make the final determination as to if the preceding object will become an obstacle such that the final obstacle verifying section gives more weight to the preliminary determination obtained with the medium accuracy method in making the final determination as the matching degree of the lane-change scene determined by the traveling scene determining section becomes higher.

23. The obstacle verification system as recited in claim 22, wherein

the preliminary obstacle verifying section is further configured to execute a high accuracy method as the at least one other verification method such that the high accuracy method involves predicting the host vehicle path based on the vehicle running state of the host vehicle detected by the vehicle running state detecting section and preliminarily determining if the preceding object will become an obstacle by comparing the host vehicle path to a detected position of the preceding object detected by the object detecting section, and

the final obstacle verifying section is further configured to make the final determination as to if the preceding object will become an obstacle such that the final obstacle verifying section gives more weight to the preliminary determination obtained with the high accuracy method in making the final determination as the degree of precision of the verification result determined by the precision determining section decreases.

24. An obstacle verification system comprising:

an object detecting section configured to detect a preceding object existing in front of a host vehicle;

a vehicle running state detecting section configured to output a running state detection result indicative of a vehicle running state;

a traveling scene determining section configured to determine a current traveling scene based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a preliminary obstacle verifying section configured to make preliminary determinations as to whether the preceding object will become an obstacle using a plurality of verification methods based on the preceding object detected by the object detecting section and the running state of the host vehicle detected by the vehicle running state detecting section;

a precision determining section configured to determine a degree of precision regarding each of the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods; and

a final obstacle verifying section configured to calculate a verification result based on the preliminary determinations obtained by the preliminary obstacle verifying section using the verification methods and based on the current traveling scene determined by the traveling scene determining section, and the final obstacle verifying section being further configured to make a final determination as to whether the preceding object will become an obstacle based on the verification result and the degrees of precision determined by the precision determining section for the preliminary determinations,

the traveling scene determining section being further configured to determine a matching degree of each of at least two prescribed traveling scenes, which includes at least a emergency scene in which an emergency avoidance measure of the host vehicle is necessary to avoid a collision and another traveling scene other than the emergency scene, with the current traveling scene,

the preliminary obstacle verifying section being further configured to execute as the verification method at least a high response method that involves preliminarily determining if the preceding object will become an obstacle based on a relative movement direction of the preceding object with respect to the host vehicle and a prescribed time value in which a movement direction of the preceding object is assumed to remain unchanged, and at least one other verification method other than the high response method, and

the final obstacle verifying section being further configured to make the final determination as to if the preceding object will become an obstacle such that the final obstacle verifying section gives more weight to the preliminary determination obtained with the high response method in making the final determination as the matching degree of the emergency scene determined by the traveling scene determining section becomes higher.

25. The obstacle verification system as recited in claim 24, wherein

the preliminary obstacle verifying section is further configured to execute a high accuracy method as the at least one other verification method such that the high accuracy method involves predicting the host vehicle path based on the vehicle running state of the host vehicle detected by the vehicle running state detecting section and preliminarily determining if the preceding object will become an obstacle by comparing the host vehicle path to a detected position of the preceding object detected by the object detecting section, and

the final obstacle verifying section is further configured to make the final determination as to if the preceding object will become an obstacle such that the final obstacle verifying section gives more weight to the preliminary determination obtained with the high accuracy method in making the final determination as the degree of precision of the verification result determined by the precision determining section decreases.

26. An obstacle verification system comprising:

object detection means for detecting a preceding object existing in front of a host vehicle;

vehicle running state detection means for outputting a running state detection result indicative of a vehicle running state;

traveling scene determination means for determining a current traveling scene based on both a longitudinal relative velocity of the preceding object that was detected with respect to the host vehicle in a longitudinal direction of the host vehicle and a transverse relative velocity of the preceding object that was detected with respect to the host vehicle in a widthwise direction of the host vehicle;

preliminary obstacle verification means for making a plurality of preliminary determinations as to whether the preceding object will become an obstacle using a plurality of verification methods, respectively, with each of the verification methods obtaining the preliminary determinations based on both the preceding object that was detected and the running state of the host vehicle that was detected;

precision determining means determining a degree of precision regarding each of the preliminary determinations that were obtained by the preliminary obstacle verification means using the verification methods; and

final obstacle verifying verification means for calculating a verification result based on the preliminary determinations that were obtained by the preliminary obstacle verification means using the verification methods and based on the current traveling scene that was determined, and for making a final determination as to whether the preceding object will become an obstacle based on the verification result and the degrees of precision determined for the preliminary determinations.

27. An obstacle detecting method comprising:

detecting a preceding object existing in front of a host vehicle;

detecting and outputting a running state detection result indicative of a vehicle running state;

determining a current traveling scene based on both a longitudinal relative velocity of the preceding object that was detected with respect to the host vehicle in a longitudinal direction of the host vehicle and a transverse relative velocity of the preceding object that was detected with respect to the host vehicle in a widthwise direction of the host vehicle;

making a plurality of preliminary determinations as to whether the preceding object will become an obstacle using a plurality of verification methods, respectively, with each of the verification methods obtaining the preliminary determinations based on both the preceding object that was detected and the running state of the host vehicle that was detected;

determining a degree of precision regarding each of the preliminary determinations that were obtained;

calculating a verification result based on the preliminary determinations that were obtained by the preliminary obstacle verification means using the verification methods and based on the current traveling scene that was determined; and

making a final determination as to whether the preceding object will become an obstacle based on the verification result and the degrees of precision determined for the preliminary determinations.