Estimation and measurement of the travel times represent an important component in traffic planning and monitoring of traffic trends. Those measurements became an integral part of intelligent transport systems. Widespread use of devices equipped with Bluetooth technology in everyday life and Bluetooth's low price of production and implementation cause Bluetooth to be used as a frequent subject in traffic research. The main objective is to assess the practicality and reliability of using Bluetooth detectors for measuring travel times on a road segment. This paper describes specifications and functionalities of Bluetooth technology, detection of Bluetooth signal, detection of Bluetooth devices from the surroundings by using MAC address and methodologies of device classification according to the travel mode. Analysis has been done for the travel times based on the data gathered from two Bluetooth detectors, which have been installed in the traffic infrastructure of the wider city center of Zagreb. Data interpretation that resulted from analysis shown within this paper indicates that Bluetooth technology can be used as a reliable and affordable system for gathering data from the traffic environment. Collected data can be furthermore analysed for various purposes, including the calculation of travel times. Although there are still some disadvantages of using Bluetooth technology as a data collecting system in traffic research, there is a large potential in the technology for observation and managing traffic networks, so as for tracking traffic participants and their movements in urban environments.