Abstract: Safe-driving was assisted with key parameters calibrated according to the driver’s characteristics
using a developed system of vehicle collision warning and collision avoidance (CW/CA). The system defines the
inverse of time-to-collision (TTC-1) as the evaluation index with the grading warning and braking safe distance
model adopted based on hazardous level ε . A millimeter waveradar obstacle detection method was designed
with adaptive cruise control (ACC). The system configuration and control logic were designed based on a Jetta
car with the collision avoidance test and the manual / automatic interaction test implemented on dry roads. The
real car experiments show that the CW/CA system in accordance with desired TTC-1 index improves vehicle
active safety, and embodies the driver’s priority and cooperation.

Key words: active safety, driving assistance, safe distance model, obstacle detection, collision warning, collision avoidance