Automobile lane changing early-warning method and lane changing early-warning system

The invention relates to an automobile lane changing early-warning method and a lane changing early-warning system. The method comprises the steps of (1) arranging the lane changing early-warning system which comprises an information collecting unit, a system control unit and an early-warning execution unit, wherein a critical safety distance computing module and an early-warning decision module are arranged in the system control unit, and a computing formula for critical safety distance which is right suitable for lane changing and an early-warning decision condition are contained; (2) collecting information of distance between the closest target automobiles in a primary lane where a user automobile is located and a lane-changing target lane in a given front-back range and the user automobile and relative speed information and speed information of the user automobile; (3) computing the critical safety distance suitable for lane changing and comparing actual distance and computed critical safety distance and generating an early-warning control instruction; and (4) sending corresponding alarming information according to the early-warning control instruction. By means of the automobile lane changing early-warning method and the lane changing early-warning system, surrounding driving environment of the user automobile can be detected comprehensively, lane-changing safety under different working conditions can be judged, and collision accidents in the lane changing process can be effectively prevented.