Reliability in the German value of time study

The German Federal Ministry of Transport and Digital Infrastructure is currently preparing the 2015 Federal Transport Investment Plan. As part of this, it is updating the overall methodology of its cost-benefit analysis meaning values of both reliability (VOR) and travel time (VOT) for personal and business travel will be estimated. While the VOTs will replace a set of existing values, the VOR will be estimated for the first time as they are not incorporated in the standard appraisal yet. The data collection adopted a two-stage approach: first respondents reported about current trips (revealed preference), which were then systematically varied to be the basis for stated preference experiments. This paper presents the findings of estimating the VOR. In the SP experiments the reliability of the travel modes was presented with different formats. The final model formulation differs in the definition of reliability for private and public transport. For car trips, saving travel time is “worthier” to the respondents than reducing the variability. The calculated VOR for the mean expected unscheduled delay of public transport trips are slightly lower than the VOTs which means that the reliability is here less important to the respondents than relevant travel time saving. One minute of mean expected unscheduled delay and one minute of standard deviation are almost equivalent to one minute of travel time saving (reliability ratio). As this has been the first official estimation of the value of reliability and time for Germany, the values should be reconsidered and updated on a regular basis