Abstract: A stepwise brake control is automatically performed when TTC obtained according to a relative distance and a relative speed between a vehicle and an object is lower than a predetermined value. For example, a brake force or a brake reduction speed is gradually increased over a plurality of stages in time series. Moreover, the affect of speed change control to the automatic brake control is removed. Alternatively, automatic brake control is supported by the speed change control. Alternatively, the friction coefficient state is estimated, and the brake force or the brake speed reduction is adjusted according to the estimated result. Alternatively, an auto-cruse function is invalidated at least the final stage. Alternatively, when the brake force or the brake speed reduction generated by a brake operation by a driver is greater than the brake force or the brake speed reduction generated by the brake control means, the brake operation by the driver is handled with a higher priority than the stepwise brake control.

Abstract: A stepwise brake control is automatically performed when TTC obtained according to a relative distance and a relative speed between a vehicle and an object is lower than a predetermined value. For example, a brake force or a brake reduction speed is gradually increased over a plurality of stages in time series. Moreover, the affect of speed change control to the automatic brake control is removed. Alternatively, automatic brake control is supported by the speed change control. Alternatively, the friction coefficient state is estimated, and the brake force or the brake speed reduction is adjusted according to the estimated result. Alternatively, an auto-cruse function is invalidated at least the final stage. Alternatively, when the brake force or the brake speed reduction generated by a brake operation by a driver is greater than the brake force or the brake speed reduction generated by the brake control means, the brake operation by the driver is handled with a higher priority than the stepwise brake control.

Abstract: A stepwise brake control is automatically performed when TTC obtained according to a relative distance and a relative speed between a vehicle and an object is lower than a predetermined value. For example, a brake pattern is modified according to the weight of a cargo and passengers. Alternatively, a driver selects a brake pattern of different (rapid or slow) speed reduction according to the type or weight of the passengers and cargo. Furthermore, the driver's psychology is acquired according to the alarm distance between vehicles set by the driver and an optimal brake pattern is selected according to this. Alternatively, an operation state of the vehicle by the driver is detected and if the detection result does not satisfy a predetermined condition, the set value of the TTC is increased. For example, the predetermined condition indicates the normal state of the driving by the driver.

Abstract: A stepwise brake control is automatically performed when TTC obtained according to a relative distance and a relative speed between a vehicle and an object is lower than a predetermined value. For example, a brake force or a brake reduction speed is gradually increased over a plurality of stages in time series. Moreover, a brake force or a brake reduction speed change ratio in the section from the rise point of a brake force or a brake reduction speed at each stage to a predetermined brake force or a brake reduction speed is made a predetermined value or a change process is made a change process along a curved shape defined by a predetermined function. Moreover, at the initial stage when gradually increasing the brake force or the brake reduction speed, an auxiliary brake is used.