  We consider open systems where cars move according to the deterministic
Nagel-Schreckenberg rules and with maximum velocity ${v}_{max} > 1$, what is an
extension of the Asymmetric Exclusion Process (ASEP). It turns out that the
behaviour of the system is dominated by two features: a) the competition
between the left and the right boundary b) the development of so-called
"buffers" due to the hindrance an injected car feels from the front car at the
beginning of the system. As a consequence, there is a first-order phase
transition between the free flow and the congested phase accompanied by the
collapse of the buffers and the phase diagram essentially differs from that of
${v}_{max} = 1$ (ASEP).
