  The theory of a jamming transition is proposed for the homogeneous
car-following model within the framework of Lorenz scheme. We represent a
jamming transition as a result of the spontaneous deviations of headway and
velocity that is caused by the acceleration/braking rate to be higher than the
critical value. The stationary values of headway and velocity deviations, and
time of acceleration/braking are derived as functions of control parameter
(time needed for car to take the characteristic velocity).
