Valuing time and reliability: assessing the evidence from road pricing demonstrations

This paper compares results from evaluations of two recent road pricing demonstrations in southern California. These projects provide particularly useful opportunities for measuring commuters' values of time and reliability. Unlike most revealed preference studies of value of time, the choice to pay to use the toll facilities in these demonstrations is relatively independent from other travel choices such as whether to use public transit. Unlike most stated preference studies, the scenarios presented in these surveys are real ones that travelers have faced or know about from media coverage. By combining revealed and stated preference data, some of the studies have obtained enough independent variation in variables to disentangle effects of cost, time, and reliability, while still grounding the results in real behavior. Both sets of studies find that the value of time saved on the morning commute is quite high (between $20 and $40 per hour) when based on revealed behavior, and less than half that amount when based on hypothetical behavior. When satisfactorily identified, reliability is also valued quite highly. There is substantial heterogeneity in these values across the population, but it is difficult to isolate its exact origins.