Monetizing Reliability to Evaluate the Impact of Transportation Alternatives

The use of reliability for evaluation of transportation alternatives depends on 1) identifying acceptable definition and quantification of reliability for use by transportation planners, engineers, and system managers, their thresholds indicating levels of performance, and, 2) monetizing reliability to evaluate the impact of transportation alternatives. To help achieve this goal, there is a need to review various definitions of reliability proposed by researchers and practitioners in the past, assess the differences in these measures to recommend the most appropriate and viable measure for use in North Carolina, define or identify thresholds indicating performance levels (additional costs incurred to users), and monetize reliability based on the recommended definition for use by North Carolina Department of Transportation (NCDOT). These objectives can be better accomplished by finding answers to the following questions. (1) What is user's perception of reliability? (2) How does their perception vary by time-of-the-day, day-of-the-week, and trip purpose? (3) What are their norms and how they relate to performance level thresholds? (4) How do these perceptions vary by user demographic and socio-economic characteristics (education level, employment or business type, earning income level, vehicle type owned, etc.)? The research team proposes the following tasks to accomplish the aforementioned objectives: 1) review reliability measures and assess the differences in estimates to recommend the most viable reliability measure; 2) define or identify thresholds indicating performance levels; 3) conduct surveys to assess user's perception of reliability; 4) interview specific target focus groups to gather user's perception and characteristics data; 5) develop a method to monetize reliability; and 6) illustrate the use of monetized reliability to evaluate the impact of transportation alternatives.