Patent ID: 8165776

Claim:
A drive assist system comprising: an assist starting part to start assist of lane change on a basis of an input of an input device; a detection part to detect relative distances and relative speeds between a vehicle and other vehicles; a calculation part to calculate collision risks to the other vehicles at a time that the vehicle changes a lane on a basis of the relative distances and the relative speeds detected by the detection part; a first judgment part to judge whether the lane can be changed or not on the basis of the relative distances, the relative speeds and the collision risks; a decision part to decide a target space for lane change on the basis of the relative distances and the relative speeds when the first judgment part judges that the lane cannot be changed; a second judgment part to judge whether there is a lane changeable space in the target space or not; a speed setting part to set a target speed for making the vehicle go to a lane change waiting position, the lane change waiting position representing a position in which a relative distance between the vehicle and a forward vehicle in the target space is shorter than a relative position between the vehicle and a following vehicle in the target space, when the second judgment part judges that there is not a lane changeable space and to set the target speed for making the vehicle go to a lane changeable position when the second judgment part judges that there is the space; and a control part to make control so that a speed of the vehicle reaches the target speed.