Development of a Concept of Operations for an autonomous tram system

Abstract

Public transportation is becoming smart and autonomous. Also trams and their operation environments are becoming autonomous, and it has been envisioned that in the near future trams could drive among other traffic in all conditions and circumstances. On the other hand, there are several challenges in the development of autonomous tram systems, since trams are operating in urban environments where high demands are set for sensors and sensor networks aiming at reliable detection of pedestrians and other vehicles. We are developing ‘The SmartRail ecosystem’ setting, which promotes transition from traditional engineering and manufacturing towards more advanced service and business ecosystem enabling a smart autonomous tram and integrated digital services for its whole life-cycle. The paper will present the development of a Concept of Operations (ConOps) for autonomous smart trams to demonstrate how they can be applied and utilized in public transportation in the future. The proposed ConOps can be considered as a boundary object in the design, validation or procurement of autonomous trams. We also propose that the ConOps should be maintained throughout the system life-cycle as an overview description and definition of overall goals and policies.A ConOps is a high-level description of how the elements of a system and entities in its environment interact in order to achieve their stated goals. The ConOps for an autonomous tram system will include, among others, the following information: overall goals and constraints of the SmartRail system, overall environmental characteristics, other stakeholders, main system elements and functions, operational states and scenarios, high-level performance requirements, system advantages and disadvantages, and human-autonomy teaming concept. Four different operational states will be considered: 1) starting a morning shift at the tram garage; 2) approaching a pedestrian crossing; 3) approaching and passing a tram stop; and 4) crossing other vehicles. The effect of seasonal conditions and weather events are also considered. A ConOps diagram has been drawn to illustrate how different stakeholders and the operating environment interact, and what kind of information is shared between different stakeholders.A special attention will be paid on the development of human-autonomy teaming concept for smart autonomous tram systems. A typical autonomous framework is based on a cross-tabulation of a scale of level of automation with stages of human information processing for a set of operational situations. We propose flexible automation solution in which the control function can be flexibly allocated to the automation or to the human operator at different phases of a tram route.Various knowledge elicitation techniques were used to gather relevant information for the ConOps: The development of the ConOps is based on a literature review, semi-structured interviews of tram drivers and trainers, and group interviews of experts working on research and development of autonomous road vehicles.