A row-crop-following system based on computer vision was installed in a J.I. Case-IH 7110 tractor. Fail-safeadaptation of the tractors steering hydraulics is described. The operator engaged or disengaged the self-steering modemuch like cruise control in an automobile. A small field of young corn was mechanically cultivated in the automaticsteering mode at 6.4 km/h (4 mile/h). The automatic-steering systems performance was comparable with steering byhuman operators.