In recent years, a consensus has been reached about the relevance of calculating the value of congestion and the value of reliability for better understanding and therefore better prediction of travel behavior. The current study proposed a revealed preference approach that used a large amount of GPS data from probe vehicles to provide insight into actual behavior in choosing a route. Mixed path size correction logit models were estimated from samples of 5,759 observations in the peak period and 7,964 observations in the off-peak period, while a mean-variance model was specified to consider both congestion and reliability terms. Results illustrated that the value of time and the value of congestion were significantly higher in the peak period because of possible higher penalties for drivers being late and consequently possible higher time pressure. Moreover, results showed that the marginal rate of substitution between travel time reliability and total travel time did not vary across periods and traffic conditions, with the obvious caveat that the absolute values were significantly higher for the peak period. Last, results showed the immense potential of exploiting the growing availability of large amounts of data from cheap and enhanced technology to obtain estimates of the monetary value of different travel time components from the observation of actual behavior, with arguably potential significant impact on the realism of large-scale models.Travel demand studies place a significant emphasis on the estimation of the value of time (VOT), namely the monetary value assigned by travelers to their travel time savings. Theoretical foundations of the VOT concept have been thoroughly reviewed in the recent past (1, 2), and empirical estimates of the VOT have been extensively provided by researchers and practitioners and meticulously reviewed (3-6).Recently, consensus has been reached about the importance of calculating two values that are related to the VOT: (a) the value of congestion, as the VOT varies with traffic conditions and relates to the complexity of driving conditions and the emergence of feelings of frustration and danger when more vehicles are present on the road [see, e.g., Fosgerau et al. (7) and Wardman and Ibañez (8)], and (b) the value of reliability, as the VOT relates to the predictability of travel time and the repeatability of the travel experience without additional costs that are attributable to uncertainty [see, e.g., Li et al. (9) and Carrion and Levinson (10)].Evidence of the value of congestion dates back about 40 years according to a report that "the estimated coefficient of auto congestion time was about thirty percent larger (in magnitude) than that of auto non-congestion time" (11). About 10 years later, a stated preference (SP) study in the United Kingdom provided the first estimates of the value of congestion, which ranged between 1.28 and 1.46 for different trip purposes (12). Then, a large variety of studies estimated the value of congestion, with values ranging from about 1.00 to mor...