Public Transport Prioritization in Consideration of Congestions

Auszug

For public transport prioritization, public transport vehicles have so far usually registered at fixed registration points (e.g., by detectors in the track for trams) in front of traffic light systems (TLS). As a reaction to the registration, a green time at the requested signal group takes place after a predefined period of time. Since there is no exchange of information between the registration locations, there are information gaps on the side of the TLS. In contrast to this, vehicles and infrastructure can now communicate continuously as a result of advancing digitalization in the transportation sector. This has already been successfully demonstrated in German projects such as VERONIKA [1]. For real-time communication, public transport vehicles were equipped with onboard equipment (OBE), and TLS with roadside units (RSU). The data telegrams, standardized according to ISO/TS 19091, could be transmitted via the short-range radio ETSI ITS-G5. In this context of cooperative intelligent transport systems (C-ITS), a vehicle can transmit its estimated time of arrival (ETA) at a stop line of a signal group. By independently analyzing the current driving status (e.g., the current speed), the vehicles networked in the C-ITS can also update the transmitted ETA-value depending on the current situation. Hepner and Noll point out potential uses (in combination with driving strategy recommendations for the driving staff) and can also include user groups such as heavy-duty transporter or bicycle traffic [2, 3]. The updatability of the ETA-value is particularly relevant when vehicles move in mixed traffic since the travel time here is very much dependent on the current traffic conditions. The obvious need arises to include the traffic jam-induced delay-times in the ETA-value. This paper presents a method how to deal with delay-times in an ETA-value. While Reich [4] compares the data included in the ETA-value in different publications, this paper focuses on which data sources are possible for the individual calculation of variables within the ETA-value. Furthermore, the question is raised whether it is always appropriate in terms of public transport prioritization to provide the TLS with an ETA-value that is as close to reality as possible. Modified ETA-values could contribute to the early clearing of the congestion on the approach to the signalized intersection, and thus have a positive effect on public transport prioritization. Different variants are compared and the respective advantages and disadvantages are analyzed. …