  We propose a microscopic traffic model where the update velocity is
determined by the deceleration capacity and response time. It is found that
there is a class of collisions that cannot be distinguished by simply comparing
the stop positions. The model generates the safe, comfortable, and efficient
traffic flow in numerical simulations with the reasonable values of the
parameters, and this is analytically supported. Our approach provides a new
perspective in modeling the traffic-flow safety and the perturbing situations
like lane change.
