Mobile phones as traffic probes: Practices, prospects and issues

The provision of road-based travel-time information often relies on speed data collected from inductive loops imbedded in the pavement. While inductive loops are commonly installed on urban freeways, they are neither configured nor ideally located to provide speed data on arterial roads. Dissemination of dynamic, network-wide travel information to road users is, therefore, likely to require alternative data collection techniques. This review considers the state of practice in relation to using mobile phones as traffic probes, assesses the prospects for this data collection option and identifies unresolved issues that may have implications for obtaining real-time traffic information using mobile phones as probes. The use of mobile phones as traffic probes is appealing because the necessary infrastructure is already in place in most urban areas. Traffic speed information can be obtained by passively monitoring data transmission in the mobile phone network. International experience provides encouraging signs about the potential of mobile phones as traffic probes. Issues still to be resolved include potential public concerns about privacy, growing awareness of the road safety implications of mobile phone use and the need to understand better the quality of the data obtained from mobile phone probes.