Abstract
Using probe car data obtained for two OD sections (31 km and 19 km) on a national highway over one year, we demonstrate the relationship between volume of probe car data and accuracy of travel time reliability indices calculated from them. Specifically, we create, as sample data sets for testing, OD travel time data sets with partial deficits that lack travel time data for some sections of all OD sections and for some days during evaluation periods. Then, we examine the difference between travel time reliability indices derived from OD travel time data sets with partial deficits and travel time reliability indices derived from those without partial deficits. As a result, we clarify the volume of probe car data required to calculate travel time reliability indices with a certain level of accuracy.
