  A simple one-dimensional spring-block model elaborated for the idealized
single-lane highway traffic reveals the causes for the emergence of traffic
jams. Based on the stop-time statistics of one car in the row, an order
parameter is defined and studied. By extensive computer simulations, the
parameter space of the model is explored, analyzed and interpreted. Existence
of a free a and congested flow phases is confirmed and the transition between
them is analyzed.
