The steering column consists of the steering main shaft which transmits the steering wheel rotation to the steering gear, and the column tube which fixes the steering main shaft to the body. The top end of the steering main shaft is tapered and serrated, and the steering wheel is fitted to it by a nut. The steering column incorporates an impact-absorbing mechanism that absorbs the thrust force that would otherwise be applied to the driver at the time of a collision. The steering column is fitted to the body via a breakaway type bracket so that the steering column can easily collapse in a crash. The bottom end of the steering main shaft is connected to the steering gear, generally by way of a flexible joint or universal joint to minimize the transmission of road shock from the steering gear to the steering wheel. In addition to the impact-absorbing mechanism, the steering main shaft on some vehicles may also contain a number of steering control systems: For example, steering lock mechanism, Tilt steering mechanism, Telescopic steering mechanism.