Drive assist system for vehicle

A drive assist system configured to be applied to a vehicle, the drive assist system comprising:

• a leading-vehicle registration determiner configured to register, as a leading vehicle, a front vehicle driving in front of the vehicle to which the drive assist system is configured to be applied, based on a preset leading vehicle register condition and to deregister the front vehicle registered as the leading vehicle, based on a preset leading vehicle deregister condition;
• and
• a front vehicle monitor configured to start to monitor the front vehicle registered as the leading vehicle regarding whether the front vehicle will perform a synchro lane change to an identical target lane, which is identical to a target lane of the vehicle to which the drive assist system is configured to be applied, on condition that the vehicle and the front vehicle are steadily driving in an identical lane,
• wherein the leading-vehicle registration determiner is configured to relax the leading vehicle register condition and the leading vehicle deregister condition when the front vehicle is being monitored, compared with when the front vehicle is not being monitored.