Autonomous driving assistance system, autonomous driving assistance method, and computer program

1. An autonomous driving assistance system, comprising:

a processor programmed to:

obtain road information that specifies classification of lanes located ahead in a direction in which a vehicle is traveling and road connection for each lane;

specify, based on the road information, a planned route that is to be taken by the vehicle on a presumption that the vehicle travels without changing lanes, when the vehicle travels with autonomous driving assistance;

if a branch point where a road branches is present ahead in the direction in which the vehicle is traveling, and a new lane added at the branch point becomes a route different from an existing lane at the branch point, specify a route along the existing lane as the planned route; and

execute the autonomous driving assistance for the vehicle according to the specified planned route.

2. The autonomous driving assistance system according to claim 1 , wherein the processor is programmed to:

if a branch point where a road branches is present ahead in the direction in which the vehicle is traveling, a merging point where a road merges is present in an opposite direction that the vehicle is traveling, and a new lane added at the merging point does not end but becomes a route different from an existing lane at the branch point, specify a route along a lane in which the vehicle is traveling as the planned route.

3. The autonomous driving assistance system according to claim 2 , wherein the processor is programmed to:

specify a merging direction of the vehicle at the merging point; and

specify, based on the merging direction of the vehicle at the merging point, the route along the lane in which the vehicle is traveling.

4. The autonomous driving assistance system according to claim 3 , wherein the processor is programmed to:

if the merging direction of the vehicle at the merging point cannot be specified specify the route along the lane in which the vehicle is traveling, based on a detection result of the lane in which the vehicle is traveling with a detection device.

5. The autonomous driving assistance system according to claim 2 , wherein the processor is programmed to:

specify the route along the lane in which the vehicle is traveling, based on a detection result of the lane in which the vehicle is traveling with a detection device.

6. The autonomous driving assistance system according to claim 1 , wherein the processor is programmed to:

specify a lane in which the vehicle is traveling; and

specify, as the planned route, a route that is to be taken by the vehicle on a presumption that the vehicle continues to travel in the specified lane.

7. The autonomous driving assistance system according to claim 6 , wherein the processor is programmed to:

if a single lane is not specified as the lane in which the vehicle is traveling and there are a plurality of candidate lanes, but a route to be taken by the vehicle is the same regardless of in which of the candidate lanes the vehicle continues to travel, specify this same route as the planned route.

8. The autonomous driving assistance system according to claim 1 , wherein the processor is programmed to:

determine if a first single route can be specified as the route that is to be taken by the vehicle on the presumption that the vehicle travels without changing lanes; and

if a single route can be specified, specify this first single route as the planned route.

9. The autonomous driving assistance system according to claim 8 , wherein the processor is programmed to:

specify a lane in which the vehicle is traveling;

if a first single route cannot be specified, determine if a second single route can be specified as a route that is to be taken by the vehicle on a presumption that the vehicle continues to travel in the specified lane based on the road information; and

if a second single route can be specified, specify this second single route as the planned route.

10. The autonomous driving assistance system according to claim 9 , wherein the processor is programmed to:

if a single lane is not specified as the lane in which the vehicle is traveling and there are a plurality of candidate lanes, but a route to be taken by the vehicle is the same regardless of in which of the candidate lanes the vehicle continues to travel, determine that the second single route can be specified as the route to be taken by the vehicle.

11. The autonomous driving assistance system according to claim 9 , wherein

map information includes information that specifies a direction along a road; and

the processor is programmed to, if a second single route cannot be specified, specify, as the planned route, a route going along a road of a route along which the vehicle is currently traveling.

12. The autonomous driving assistance system according to claim 1 , wherein the processor is programmed to:

detect a vehicle maneuver that controls the vehicle to change lanes as a lane change vehicle maneuver; and

if the lane change vehicle maneuver is detected, cancel the currently specified planned route and specify the planned route again based on a new vehicle condition after the lane change vehicle maneuver.

13. The autonomous driving assistance system according to claim 12 , wherein the processor is programmed to:

set, as a control intervention monitoring section, a section where there is a possibility that the planned route is changed due to a lane change of the vehicle; and

if the lane change vehicle maneuver is detected while the vehicle is located in the control intervention monitoring section, cancel the currently specified planned route and specify the planned route again based on a new vehicle condition after the lane change vehicle maneuver.

14. The autonomous driving assistance system according to claim 12 , wherein

the lane change vehicle maneuver is an operation of displacing a steering of the vehicle to a predetermined angle or more.

15. The autonomous driving assistance system according to claim 1 , wherein

if a branch point where a road branches is present ahead in the direction in which the vehicle is traveling, the road information includes information about a line type of a lane marking at the branch point and information about a connection type of a lane before the branch point.

16. The autonomous driving assistance system according to claim 15 , wherein

the information about the connection type of the lane is information specifying that the lane is “add,” “continue,” “end,” “divide,” or “merge”.

17. An autonomous driving assistance method, comprising the steps of:

obtaining road information that specifies classification of lanes located ahead in a direction in which a vehicle is traveling and road connection for each lane;

specifying a planned route that is to be taken by the vehicle on a presumption that the vehicle travels without changing lanes, based on the road information, when the vehicle travels with autonomous driving assistance;

if a branch point where a road branches is present ahead in the direction in which the vehicle is traveling, and a new lane added at the branch point becomes a route different from an existing lane at the branch point, specifying a route along the existing lane as the planned route; and

executing the autonomous driving assistance for the vehicle according to the specified planned route.

18. A computer-readable storage medium storing a computer-executable program that causes a computer to perform the following functions:

obtaining road information that specifies classification of lanes located ahead in a direction in which a vehicle is traveling and road connection for each lane;

specifying, based on the road information, a planned route that is to be taken by the vehicle on a presumption that the vehicle travels without changing lanes, when the vehicle travels with autonomous driving assistance;

if a branch point where a road branches is present ahead in the direction in which the vehicle is traveling, and a new lane added at the branch point becomes a route different from an existing lane at the branch point, specifying a route along the existing lane as the planned route; and

executing the autonomous driving assistance for the vehicle according to the specified planned route.