Vehicle collision avoidance and warning system

A method for providing collision avoidance in a host vehicle, said method comprising:

• defining first, second, third and fourth thresholds that identify a time to collision with a target vehicle by the host vehicle that are based on a speed of the host vehicle, an acceleration of the host vehicle, a speed of the target vehicle, an acceleration of the target vehicle, a distance to the target vehicle from the host vehicle and a coefficient of friction of a roadway on which the host vehicle and the target vehicle are traveling, where the first threshold is greater than the second threshold, the second threshold is greater than the third threshold and the third threshold is greater than the fourth threshold;
• determining, in a processor, if the time to collision is less than the first threshold, and if so, initiating a collision warning;
• determining, in the processor, if the time to collision is less than the second threshold if the time to collision is less than the first threshold, and if so, providing limited automatic braking of the host vehicle;
• checking a condition of whether a roadway lane adjacent to the host vehicle is clear;
• determining, in the processor, if the time to collision is less than the third threshold if the time to collision is less than the second threshold;
• providing full automatic collision avoidance braking if the time to collision is less than the third threshold and the lane adjacent to the host vehicle is not clear;
• determining, in the processor, if the time to collision is less than the fourth threshold if the time to collision is less than the third threshold and the lane adjacent to the host vehicle is clear;
• and
• providing both automatic host vehicle steering and host vehicle braking in the host vehicle if the time to collision is less than the fourth threshold and the roadway lane adjacent to the host vehicle is clear.