Modern transit agencies increasingly are communicating real-time information, such as schedules, upcoming events and relevant emergency information, to their customers using passenger information signage.

As communication technologies have evolved, travelers also have become accustomed to receiving entertainment and other information, such as news, weather and traffic relevant to the location, via digital passenger information signs — a form of dynamic display in which content and messages displayed on an electronic screen can be changed without modification to the physical sign.

While the main purpose of passenger information signs is to deliver targeted messages to specific locations at specific times, these digital networks also enable operators to interrupt their normal messaging when emergency situations arise.

The operation of digital signage networks for transportation is unique, as the relevance of weather, traffic and emergency information can be quite different across what is normally a large network that can reach thousands of passengers.

For example, school closings, traffic jams and network delays may be relevant only to certain locations within the network. Travelers in other locations may need to receive weather or safety messages. The ability to target travelers with information that is relevant only to them also provides a unique opportunity to support messages from local law enforcement and public safety officials.

The advancement from simple LED signs to a more sophisticated digital sign not only enhances the way information is presented to the public, it also affects the type of information that can be displayed.

Increasingly, transit agencies are taking advantage of digital signage technologies to build information networks that provide the right information to the right location, at the right time and on the right display.

Digital signage can improve communications through its ability to present dynamic information on a single, high-quality display that includes video, audio, text and graphics. These same technologies allow targeting of any of these rich media communications messages to groups, sub-groups or individual displays as required.

The ability to target specific information to specific displays also offers the potential to open new revenue streams, such as leasing signage space for product advertising, or delivering promotional campaigns that target point-of-purchase sales within the networks themselves.

A well-operated digital signage network enhances the entire experience for everyone — from the transit agency to the system operator to public safety officials to the passenger at the station. The agency benefits from a scalable, point-to-multipoint architecture that can disseminate information to multiple displays at multiple destinations, localizing targeted content as required.

The signage network operators have a flexible system with automated technologies at their fingertips that, when coupled with the IP environment, create a powerful, easy-to-operate network for video, audio and data distribution.

Public safety officials gain valuable, timely access to a channel that can be used to communicate critical information to the traveling public when the need arises. Meanwhile, passengers stay informed of pertinent information through consistent real-time updates. They also can be entertained with high-quality video while awaiting the next bus, train or subway car.

Modern IP networks offer the most cost-effective approach for deploying a point-to-point and multipoint signage network. They support multiple network topologies and can be implemented to support both wired and wireless connectivity, which provides more flexibility for the distribution of video, audio and data content.

Operators can effectively manage the signage network resources, as well as target content such as weather information, advertising, graphics or simple text crawls to many screens or to a specific display. Devices at each endpoint can be assigned a static IP address, which makes it easy to target the content. Because there are two levels of addressability, one within the network and one at the location, display operators can target content to specific locations within displays throughout the signage network.

Most digital signage networks are made up of three key elements:

  1. The player — an individual remote system that displays the required content for a given project or presentation. The player can be notified of content changes from the central network manager and will download the necessary files and play updated presentations from its local hard drive. Each player can connect to local copies of specified data sources, providing live local text and data content within the presentation.

  2. A content management workstation, which allows network operators to centrally create and edit all projects, including the page layouts specific to a display. The content management workstation also manages the content and schedules on any player.

  3. A set of network content management tools. Operator control begins at the network operations center (NOC). Control of the players is handled by a single operator from a central workstation, which deploys automatic, real-time updates to players' displays.

The network manager defines which player(s) the presentation is intended for and when it needs to arrive. The network manager then publishes the necessary files to a specified file server location (such as a high-bandwidth server) and notifies the specific player(s) to retrieve modified presentations from the central file server.

Using one network manager (and file server), a single person can control an entire local or global digital signage network; the ability to define player groups allows complete control over localized presentations. Each group of players can be viewed as a separate signage network, or as a variation of a network-wide presentation.

More complex signage networks that are graphics rich and/or support multiple satellite feeds, ad management and billing software require more operators. Regardless, these tasks are all handled at the NOC, keeping the operators in one place and focused on the distribution model.

The ability to communicate emergency-related information to the traveling public is an important function of the digital signage network. Content players can broadcast emergency messages, alerts or notifications, which can be triggered across the network. Emergency alerts could be live video evacuation messages, audio alerts and notifications or simple text-based messages.

Because the messages and triggers can be distributed to a specific display, the signage network and the public safety sector can be tied together to target messages to a local community.

Critical public information, such as an Amber Alert or a tornado warning, can be given priority once fed into the network, interrupting the current display information in favor of the emergency message. Moreover, the open architecture of the IP network means that a local police or fire department, in cooperation with the local transit agency, could access the network remotely to trigger public safety announcements.

The same triggers can interrupt general video/audio/data feeds to display emergency notifications from a national signage network. For example, the Department of Homeland Security could initiate a national alert that could translate to regional and local signage networks. This hierarchical communication system is not only ideal for transportation signage networks, but also for signage networks in and around communities.

The IP architecture also offers the potential for integration of the digital signage network with other technologies at the transportation hub. One possibility is integrating parts of the transit operation at a train station, including signaling and scheduling applications.

For instance, a typical railway has a series of triggering devices along the tracks that communicates with a rail system database, pinpointing the current location of a train and when it will arrive at the next station. This information can be displayed to passengers, using hooks built into the system to display the signaling and scheduling information received from a database.

Translating the fixed digital signage network to the mobile environment is not far off. Today it is possible, with IP connectivity, to allow the same real-time updates to displays in a moving train.

The biggest hurdle is establishing consistent connectivity throughout the trip; this is especially difficult in tunnels or mountainous terrain where connectivity is more easily interrupted. Strides continue to be made in the mobile environment as technologies for reliable connectivity improve.

Travelers today are more accustomed to visual communication than ever before. The digital signage network is a natural evolution from other modern technologies that disseminate information quickly and effectively.

For public safety organizations and transit authorities, digital signage offers superior return on investment compared to traditional printed signs because of its dynamic, real-time nature. Applications include targeted transit information, emergency messaging and integration with community databases. National security in the form of emergency messaging and notification is at the forefront.


John Delay is the director of strategic management for the government solutions unit of Harris Broadcast Communications.