Heavy vehicle traffic across the European Alps has been growing steadily during past decades. Environmental impacts along the narrow alpine corridors and severe traffic incidents in tunnels have stirred a wide discussion about the future development of transalpine road traffic and about drastic measures to restrain truck volumes and to increase tunnel safety. The paper describes the heavy vehicle management system introduced in Switzerland in December 2001 following the Gotthard fire catastrophe. The traffic management system comprises minimum distance between heavy vehicles in tunnels, alternating one-way traffic for trucks in long tunnels and speed reduction for trucks in tunnels and on access ramps. One-way traffic for trucks in bi-directional tunnels is primarily intended to increase the safety in tunnels. When truck drivers keep to a minimum inter-truck distance of 150 m then at no time will more than one truck be involved in a tunnel accident. This structurally reduces the risk of a catastrophic fire. The initial system has proven to work but leaves room for optimization and improvement, in particular with respect to the "disproportionate" waiting times. Two optimization alternative packages are currently considered to further optimize the system and to ease the "disproportionate waiting time" problem. One is based on the retention and further optimization of the one-way alternating metering scheme. The other is based on a new bi-directional metering scheme. This paper also accounts for the gained operational experiences as well as the measures associated with the two alternative optimization packages.
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