Evaluating Alternative Operations Strategies to Improve Travel Time ...

SHRP 2 L11: Final Appendices
unreliability in travel times is experienced, the cost of unreliability to users on the facility over a
one-hour period is approximately $20,000 (1 minute/mile X 33.33 cents/minute X 10 miles X 6000
= 2,000,000 cents or $20,000). This concept for calculating the value of travel-time reliability is
illustrated in Figure B.1.
Figure B.1 – Concept for Valuing Travel-Time Reliability
The concepts for determining the economic benefits for improving travel-time reliability are
presented in detail in the following sections of this appendix:
• Measuring the Value of Reliability
• Valuing Reliability for Recurring Events
• Measuring Network-wide Impacts
• Quantifying the Value of Time
• Applying the Methodology
• Conclusions for the Options Theoretic Approach
• Recurring-Event Reliability Valuation Example
Measuring the Value of Reliability
Evaluating the economic cost of unreliability on the highway system requires a method for valuing
reliability. This, in turn, requires measuring unreliability in a consistent manner and a method of
placing a value on the costs of unreliability. The methodology outlined in this section provides a
consistent means for characterizing reliability and for valuing reliability using the value of time
measures described above. This methodology is adaptable to both recurring reliability issues and
DETERMINING THE ECONOMIC BENEFITS OF IMPROVING TRAVEL-TIME RELIABILITY Page B-3