On the other hand the dollars spent per unit of hazard at sites 1 and 5 are substantially more those spent at site 2. The difference is closure policy. At site 2 longer closures are applied to control the hazard and this can be accomplished at low cost. Sites 3 and 4 on the other hand have a wide gap between the dollars per unit AHI and the dollars per unit hazard reduction. This reflects the more passive control strategy on these routes where traditionally avalanches have been allowed to block the road before the road is closed.
Fewer dollars are spent on active control operations, however a greater risk is accepted.
The avalanche hazard index, residual hazard and the concept of hazard reduction are valuable tools in analysis of current highway operations. The value of the transportation network as a key economic asset has not been discussed in this paper, however, this element must be included in comprehensive cost benefit analysis. Closure policy must also be determined prior to identification of control strategy. The general recommendations of the Five Mountain Parks Highway Avalanche Study included increased use of the 106 mm recoilless rifle, highway relocation and earthworks, maintenance and additions for snowsheds, a park wide data acquisition 7 management system, a training center at Rogers Pass and an integrated traffic management plan with adjacent jurisdictions. B.R. A Quantitative Analysis of Avalanche Hazard on U.S. Highway 550, Southwestern Colorado, Western Snow Conference, 1981.