TIH Principles Overview
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The TIH Executive Group
To support the travel information marketplace...from spotting an opportunity to making an information exchange. Version 6.0 - August 2006
Foreword
Most travellers neither know nor care who operates the road, bus or train they are travelling on; they just want to know which service or route to take and if the way ahead is clear.
This lack of distinction is crucial for travel information providers, because the way we divide up our networks into operator-sized chunks is largely meaningless in the minds of the people we are trying to reach.
The solution, of course, is to pool travel information and make it available in ways that make the boundaries between providers largely invisible to the end-user and to give a joined-up view of the transport network.
But (and it’s a big but) we are not starting from a clean sheet of paper.
Countless organisations, from local authorities and government agencies to train and bus operators, have invested in systems to manage their own information on urban traffic, motorway incidents, timetables and parking; in fact every conceivable data-type for every mode of transport. What’s more, few of these systems share a common language so they can’t talk to each other.
The benefits of sharing data are clear - both for informing travellers and improving how we manage events across local boundaries – but we can see how complex this might be. Thankfully, help is at hand...
Stephen George
TIH Chief Executive Officer
Executive Summary
The aim of the TIH Community is to help members build universal system-to-system links to exchange travel information, saving money, time, duplication and effort over the ‘build your own’ model that had prevailed in the past.
By sharing experiences, the TIH Community has distilled its knowledge into a framework of guidelines known as the TIH Principles, a set of simple rules to define a common approach based on proven techniques and best practice.
Following the TIH Principles makes sure that we all make our data available in a common format and use common standards for locations, event types, etc.
Computers don’t like surprises. To effectively exchange information, the format of the data needs to be agreed in advance. If the data doesn’t match exactly what the receiving system is expecting to see, the exchange will fail.
The TIH Principles do not compromise your data ownership, nor do they imply a data warehouse. TIH is not a system in itself, just the agreed framework for joining many systems together over the Internet and it sets out the rules for these key areas of data exchange:
- The Charging Mechanism should be clearly described.
- The Authentication Level should match the value of the data.
- Data should be published using XML with compression.
- Data and Publication Models should be described adequately.
- For location referencing use TPEG-Loc or at least WGS84.
As you can see, there’s no mystique or complexity to the Principles – just some common-sense approaches that we can all work with.
The TIH Principles are developed and recommended by independent members within a series of Working Groups. Each group is led by a recognised expert in that area. Up to date documentation, discussions and support on each area is accessible on our website.
If you would like to learn more about how your organisation would benefit by getting involved, just register via the membership page.
You can access the full TIH documentation including the TIH Principles, a weekly digest of current activities, the Technical Appendix which explains exactly what your technical people need to do, and the Business Appendix which includes case studies and sample contracts for your commercial team.
You can also contact members of the TIH Executive through the [Helpdesk] if you would like to discuss any aspect of TIH or need some support or technical advice to help get your organisation on board.
The TIH Principles
Click here for a list of the 5 main Principles
Background to this document
Few problems are completely novel, and many organisations share similar requirements and have faced the same obstacles before.
Ten years ago, a group of local authorities, broadcasters, network operators (including the Highways Agency) and public transport companies came together to form the Travel Information Highway Community. The aim of the TIH Community is to help members build universal system-to-system links to exchange travel information, saving money, time, duplication and effort over the ‘build your own’ model that had prevailed in the past.
By sharing experiences, the TIH Community has distilled its knowledge into a framework of guidelines known as the TIH Principles, a set of simple rules to define a common approach based on proven techniques and best practice. A “checklist” of the Principles is given in Section 2, and a full explanation of the TIH Principles can be found on the TIH website at www.tih.org.uk.
Using the TIH Principles, some pioneer users including the Highways Agency, BBC and Trafficlink have adopted and refined a number of existing specifications to cover all kinds of travel and traffic information.
All the TIH recommendations share the TPEG Loc location referencing that adds road name, direction of travel and other details to the international latitude/longitude reference standard WGS 84.
Full descriptions of each specification can be found on the website if you’d like to delve into the details, but the simplest way to explain how these standards work is to think of them like a simple, standard plug.
The context of electronic exchange of travel information
Exchanging information - plug and play
Remember the hassle of getting computers, printers and other kit to talk to each other before the advent of USB?
We had parallel and serial cables; different kinds of serial ports with nine or fifteen pins; special plugs for keyboards and mice. The standards were confusing and wasteful, and setting up a new printer might swallow a whole morning.
With USB – as with the TIH interfaces – you know that the same plug will work anywhere. You buy a new mouse, plug it in, and carry on working.
With the TIH OTAP specification, to take one example, if your traffic data is packaged by your own system and made available on a web-server, then everyone who you give permission to can see it and use it. No-one will come asking for the data in a different format, because they have the power to do that for themselves without any extra work at your end and without altering the data on your system.
What’s more, if someone can use your OTAP service, then you can probably use theirs. This is a valuable benefit now that more and more travel and transport organisations are collaborating to better manage the interfaces between them.
For those in Local Highways Authorities this is even more useful now the Traffic Management Act of 2004 has created a statutory duty to facilitate the flow of traffic on their own network and on those of their neighbours.
TIH Exchange - How does it work
Computers don’t like surprises. To effectively exchange information, the format of the data needs to be agreed in advance. If the data doesn’t match exactly what the receiving system is expecting to see, the exchange will fail.
Following the TIH Principles makes sure that we all make our data available in a common format and use common standards and specifications for locations, event types, etc.
The Principles recommend language independent look-up codes with descriptions substituted by whatever system reads the file. This means that data is easy to use in any language without the need for translation – for use in tourist information for instance.
The TIH Principles do not compromise your data ownership, nor do they imply a data warehouse. TIH is not a system in itself, just the agreed framework for joining many systems together over the Internet and it sets out the rules for these key areas of data exchange:
- The charging mechanism for the data should be clearly defined
- Security levels should match the value of the data
- Location references should follow international standards
- The format of the data should be described adequately
- Data should be published using XML
As you can see, there’s no mystique or complexity to the Principles – just some common-sense standards that we can all work with.
The basis of the TIH model is the exchange of information between:
- an Information Publisher, wanting to make information available and
- an Information Receiver, seeking to obtain information.
In most cases organisations will have both Information Publishers and Information Receivers but the distinction helps to separate the two sides in any exchange.
TIH Principles: recommended by experts – approved by users
The TIH Principles are developed and recommended by independent members within a series of Working Groups. Each group is led by a recognised expert in that area.
All members are welcome to contribute to the Working Groups, which currently cover the following areas:
- ITS Data Content Definition: how we describe the data we exchange.
- ITS Interfaces: how we exchange data technically.
- ITS Location Referencing: how we describe where something is on a road or public transport network.
- Data Quality: how we describe service levels and the quality of the data.
- TIH Communications: our way of communicating with ITS professionals.
- TIH Mobile: delivering information to mobile devices.
The TIH Community co-operates with urban traffic management developments through the Urban Development Group and bus information through the Real Time Information Group. More details of this co-operation are given in Section 6 – the TIH/RTIG/UDG Joint Initiative.
TIH Community: A long-term investment
Since its inception in 1996, the TIH Community has been working toward the goal of better travel information exchange. The Secretary of State for Transport has guaranteed fundamental administrative support for the TIH Community until at least 2011. Information Publishers and Receivers can therefore be assured that the longevity of the TIH Principles are guaranteed.
