Vehicle speed control device

1. A vehicle speed control device comprising:

a parallel running vehicle detection sensor configured to set an adjacent lane as a detection area, the adjacent lane being adjacent to a traveling lane where a vehicle travels; and

an electronic control unit configured to

control a speed of a vehicle,

perform cruise control for controlling the speed of the vehicle such that a predetermined cruise condition is implemented,

perform, based on an output of the parallel running vehicle detection sensor, parallel running vehicle detection processing for detecting a parallel running vehicle traveling in the adjacent lane of the vehicle,

perform blind zone avoidance control for controlling the speed of the vehicle such that the vehicle is moved to a position behind a blind zone of the parallel running vehicle when the parallel running vehicle is detected during execution of the cruise control,

perform blind zone getting-out determination processing for determining whether the vehicle can move to a position ahead of the blind zone by traveling according to the cruise condition, and

perform avoidance cancellation processing for prioritizing the control of the speed by the cruise control over the control of the speed by the blind zone avoidance control when it is determined by the blind zone getting-out determination processing that the vehicle can move to the position ahead of the blind zone,

wherein the vehicle is prioritized to move from the position behind the blind zone of the parallel running vehicle to the position ahead of the blind zone of the parallel running vehicle when a distance between a proceeding vehicle of the vehicle in the traveling lane is greater than a sum of a target distance determined by the cruise control condition, a length of the blind zone in a traveling direction of the vehicle, and a length of the vehicle.

2. The vehicle speed control device according to claim 1 , further comprising an inter-vehicle distance sensor configured to detect an inter-vehicle distance between the vehicle and the preceding vehicle of the vehicle in the traveling lane, wherein

the cruise control includes tracking cruise control for causing the vehicle to travel by tracking the preceding vehicle,

the cruise condition includes a condition for setting the inter-vehicle distance as the target distance, and

the blind zone getting-out determination processing includes processing for determining, when a current inter-vehicle distance between the vehicle and the preceding vehicle is larger than a sum of the target distance and the length of the blind zone in the traveling direction of the vehicle, that the vehicle can move to the position ahead of the blind zone.

3. The vehicle speed control device according to claim 1 , further comprising an inter-vehicle distance sensor configured to detect an inter-vehicle distance between the vehicle and a preceding vehicle of the vehicle in the traveling lane, wherein

the cruise control includes tracking cruise control for causing the vehicle to travel by tracking the preceding vehicle,

the cruise condition includes a condition for setting the inter-vehicle distance as a target distance, and

the blind zone getting-out determination processing includes: (i) processing for detecting a speed of the preceding vehicle; (ii) processing for detecting a speed of the parallel running vehicle; and (iii) processing for determining, when the speed of the preceding vehicle is higher than the speed of the parallel running vehicle, that the vehicle can move to the position ahead of the blind zone.

4. The vehicle speed control device according to claim 3 , wherein

the cruise condition includes a condition for preventing the speed of the vehicle from exceeding a specified vehicle speed, and

the blind zone getting-out determination processing includes processing for determining, when the speed of the parallel running vehicle is equal to or lower than the specified vehicle speed, that the vehicle can move to the position ahead of the blind zone.

5. The vehicle speed control device according to claim 1 , wherein

the cruise control includes constant speed cruise control for causing the vehicle to travel at a specified vehicle speed,

the cruise condition corresponding to the constant speed cruise control includes a condition for setting the speed of the vehicle to the specified vehicle speed, and

the blind zone getting-out determination processing executed under the constant speed cruise control includes processing for detecting a speed of the parallel running vehicle and processing for determining, when the specified vehicle speed is higher than the speed of the parallel running vehicle, that the vehicle can move to the position ahead of the blind zone.

6. The vehicle speed control device according to claim 2 , wherein

the cruise control includes constant speed cruise control for causing the vehicle to travel at a specified vehicle speed,

the cruise condition corresponding to the constant speed cruise control includes a condition for setting the speed of the vehicle to the specified vehicle speed, and

the blind zone getting-out determination processing executed under the constant speed cruise control includes processing for detecting a speed of the parallel running vehicle and processing for determining, when the specified vehicle speed is higher than the speed of the parallel running vehicle, that the vehicle can move to the position ahead of the blind zone.

7. The vehicle speed control device according to claim 6 , wherein

the electronic control unit is configured to perform, during execution of the tracking cruise control:

(i) processing for determining whether there is the preceding vehicle in the traveling lane; and

(ii) processing for switching the tracking cruise control to the constant speed cruise control when the preceding vehicle has gone from the traveling lane.