 the transverse acceleration, a.sub.y. This reduced assisting force results, on one hand, from the transverse acceleration, a.sub.y, when the transversely dynamic limit region is reached under normal roadway conditions and, on the other hand, from the transverse acceleration, a.sub.y, when the transversely dynamic limit region is reached under the instantaneously determined roadway conditions.
Roadway slipperiness which occurs can also be recognized by a deviation of the force in the steering linkage when cornering from a reference value of the force in the steering linkage under optimum roadway conditions or from the appearance of signals, or their effects, from a drive-slip control (DSC) or from the appearance of signals, or their effects, from an antilock braking system (ABS). The effects of the signals associated with the ABS can be the brake pressures appearing at the individual wheels or the forces on the brake calipers or brake drums determined in a manner known per se. In addition, a possible effect of the signals from a DSC is a reduction in the engine torque, which reduction is preferably produced by the position of the throttle valve or of the control rod being manipulated. In principle, the extent of the requisite reduction in the assisting force in the power-assisted steering can be derived from any of these specified means of determining the roadway slipperiness.
Differences in the steering behavior of the vehicle which result from different loading states of the vehicle are compensated in an advantageous manner by suitably varying the assisting force in the power-assisted steering as a function of the loading state. In principle, it is possible to vary the characteristic diagram of the assisting force in the power-assisted steering by a discretization with regard to the loading state of the vehicle. However, an accumulation of a large quantity of data on account of the discretization with regard to the loading state can be avoided by two characteristic diagrams of the assisting force being included