Evaluating Alternative Operations Strategies to Improve Travel Time ...

SHRP 2 L11: Final Appendices
increases, say from K=5 to K=10 as shown below, F(V), also expressed as millions of dollars,
decreases. Figure C.7 demonstrates the relationship between the project value and the number of
avalanche closures. This figure is for illustrative purposes, only, because the Gumbel was
estimated only for the avalanche incidence on one pass (I-90) and may not represent the incidence
of conditions that cause avalanches on multiple passes. However, it reveals the expected result,
i.e., that a project or strategy intended to remediate multiple avalanches does not have high value
because it is such a rare event.
Figure C.6 - Certainty Equivalent benefit for Different Mitigation Costs, K
Figure C.7 - Sensitivity of F(V) to different Numbers of Avalanche Closures per Month
2.5
2.0
1.5
1.0
0.5
0.0
0 2 4 6 8 10 12
Number of Closure Events, X
VALUATION OF TRAVEL-TIME RELIABILITY FOR RARE EVENTS Page C-12