Publication: Validation and usability of floating car data for transportation policy research

This paper describes whether Floating Car Data (FCD) are usable for policy research in the Netherlands based on validation criteria. The use of FCD for traffic information, traffic management and automated vehicles is however beyond the scope of this paper. Projects undertaken by the Netherlands Ministry of Infrastructure and the Environment reveal that for identifying bottlenecks on national, regional and local roads, FCD, owing to the spatial and temporal detailing of vehicle driving speeds, have considerable advantages over data from fixed measurement points.

INRIX and TomTom annually publish traffic rankings of cities in the Netherlands, but they are not useful for policy, as their findings are inconsistent and largely incomprehensible. To determine whether FCD can be used to identify trends over succeeding years the KiM Netherlands Institute for Transport Policy Analysis (KiM) compared speeds from FCD 2011-2014 (HERE) and 2014-2016 (INRIX) with driving speeds based on induction loops. Our first conclusion is that over the years FCD elicit certain misrepresentations, because different sources of FCD are used, definitions change (e.g. in road segments), and data are filtered or substituted for missing periods of time. Our second conclusion is that it appears to be possible to monitor trends in hours of delay with a method we developed combining FCD with induction loop data. The use of mobile data for ex-ante and ex-post policy evaluations is currently in an explanatory stage in the Netherlands. Projects aim to improve the measurement of travel time from origin to destination in disaggregated traffic models.