Validation of ATIS journey time and traffic speed estimates by floating car survey

Traffic congestion is a re-current problem in densely populated cities. To alleviate congestion, many countries/cities have developed advanced traveler information systems (ATIS) to provide the latest traffic information to road users. However, the traffic information such as instantaneous journey time and traffic speed provided by ATIS is difficult to be validated. In particular, instantaneous journey time reflects the current traffic condition in terms of travel time at different road segments at the same instant. No single driver can normally experience the instantaneous journey time except for travelling on a very short section of road under light trafficked condition. This paper proposes a methodology for validating the instantaneous journey times and traffic speeds with independent observed data. The results show that the proposed method can validate the instantaneous journey time and traffic speed estimates satisfactorily with adequate sample sizes at a significant level statistically.