A steering control system includes a steering wheel and a steering shaft
with upper and lower shaft portions. Steering shaft torque of the lower
shaft portion corresponds to torque transmitted to the upper shaft
portion, and steering shaft torque steers vehicle wheels. A steering
torque detector is included for detecting steering torque. An assist
force generating device generates assist forces according to a control
signal to thereby generate torque in the lower shaft portion. A
controller is included for outputting the control signal based upon the
steering torque. A vehicle speed detector detects speed of the vehicle,
and an environment information detector detects environment information.
A basic assist amount is set according to the vehicle speed and the
steering torque, and a torque correction amount is determined based upon
the environment information. Additionally, the assist force is determined
based upon the basic assist amount and the torque correction amount.