Experiments and experiences on the relationship between the probe vehicle size and the travel time collection reliability

It is obvious that more probe vehicles guarantee better reliability of travel time data collection. Because of cost involved, increasing the probe vehicles is not always possible. Thus, the mechanism of the relation between the probe vehicle size and the travel time data collection reliability needs to be investigated for optimizing the ATIS implementation, On the relationship between the probe vehicle size and the travel time collection reliability, this study contains two different kinds of data in two test networks. One came from simulation based experiments and the other came from field experiences of a real time travel time collection system. There are a bit comprehensive differences between the results of experiments and experiences. The similar trend has been observed in both networks. In spite of many possible sources of the differences, it can be learned that in selecting probe vehicles, the operational characteristics of vehicles are very important to construct reliable information systems to guarantee to meet network coverage requirements. Furthermore, the effectiveness of probe size increases marginally decreases.