Travel time reliability value and thresholds in North Carolina

The focus of this paper is to identify thresholds and monetize travel time reliability to evaluate transportation projects/alternatives. Stated preference survey was designed to capture perceptions of North Carolina motorists. A random survey was carried out across the cities and towns in North Carolina, and 334 valid responses were gathered from the participants. The results indicate that 60.8% of the random survey participants were willing to take an unreliable route with travel time varying from 20 to 30 minutes, whereas the remaining 39.2% of the random survey participants prefer a reliable 25-minute route. As the variation in travel time increased on the unreliable route, random survey participants preferred to opt for a reliable route over an unreliable route. Four days of unreliability per month was acceptable for only 33.8% of the random survey participants. They shifted from an unreliable route to a reliable route with an increase in the number of unreliable days in a month. Overall, the generalized value of buffer time from the random survey is estimated equal to $0.45 per minute. Differences in the value of buffer time were observed between cities, towns, and other areas across North Carolina. While a higher percentage of focus group survey participants preferred the reliable route, the value of buffer time based on data collected through focus group survey is also comparable to the random survey-based value.