most needed. Information overload must be avoided. Latency or response time. Information provision must react quickly to a passenger request or a real-world update. There is little point in announcing a service three minutes after it has departed. Real-time arrival prediction systems Current operational information on service running is collected from automatic vehicle location (AVL) systems and from control systems, including incident capture systems. The information can be compared algorithmically with the published service timetable to generate a prediction of how services will run in the next few minutes to hours. That may be informed by additional information. For instance, bus services are affected by congestion on the road network, and all services may be affected by adverse weather conditions. Economic rationale The capital and revenue costs for traveller information systems can be calculated with reasonable accuracy. However, the derivation of tangible financial benefits is far more difficult to establish and as so there is very little research. That directs the business model for information systems towards the "softer" merits such as traveller confidence. It is worth noting that there must be an actual value, as individuals are willing to pay for systems that give them access to real-time data relating to their journey. The difficulty is establishing what that is for each individual person and perhaps each individual piece of roadside hardware. Even less is known about the long-term effects of access to these types of services. The only long-term study is from 2012. Communication channels Information may be delivered via any electronic media, including: Mobile phone application LED displays and screens inside stations E-paper displays and screens at bus stops and shelters Internet through a website Telephone (either a staffed bureau service or an automated answering system) Touch screen kiosks for self-service (e.g. in customer offices) Additional considerations include: How the system presents information for disabled travellers Whether the system provides information in multiple languages Information The information provided by a passenger information system depends on its location and the technical scope (e.g. the size of the display screen) At a station or stop, it is normal to provide up-to-date predictions of: Which service is operated by the next vehicle to arrive, including its route and destination. When the vehicle will arrive. How closely it is running to timetable. Similar information for the following few services. General advice on current travel disruptions that may be useful to the