A few multi-country highway design standards exist. Three examples relate to roads in Europe, Asia and Africa.
The UNECE document on Trans-European motorways (ref. 726, of 2002) includes recommended figures for some features of highway geometric design. This third edition of the “TEM standards and recommended practice” is based on the original TEM standards of 1981. The introductory text says:
Although their primary application will be to the Trans-European North-South Motorway, these standards are at disposal to other United Nations countries which find them beneficial for the formulation or updating of their national standards.
Wikipedia (link) explains that “the Asian Highway (AH) project, also known as the Great Asian Highway, is a cooperative project among countries in Asia and Europe and the United Nations Economic and Social Commission for Asia and the Pacific (ESCAP), to improve the highway systems in Asia”. The related document, the Asian Highway Handbook (ref. 756 of 2003) includes recommended figures for a number of highway geometric design parameters. The text explains that:
The main obligations of the Contracting Parties within the Agreement are to adopt the Asian Highway network as a coordinated plan for the development of highway routes of international importance; bring the network in conformity with the Asian Highway classification ….
Asian Highway routes are required to conform to minimum standards of classification and design in terms of construction, improvement and maintenance.
A document called the SATCC “Draft Code of Practice for the Geometric Design of Trunk Roads” (ref. 771 of 2001) refers to the member states of the Southern African Development Community. The foreword says that
“…. geometric design guidelines should be specifically oriented towards southern African conditions” and that “…. the objectives of uniformity and local relevance should be more actively pursued than in the past”.
The following table gives some geometric values from the three regional documents.
It would probably not be difficult to replace the separate documents with one common set of guidelines – with exceptions being made for local circumstances. This would meet the two, essentially contradictory arguments brought out in the quote from the SATCC document (ref. 771), namely:
- that the objective of uniformity should be more actively pursued, and
- that geometric design guidelines should be oriented towards local (southern African) conditions.
The question then is at what scale does a design guideline become”local” ? For example, if someone produced a global set of guidelines from the above three documents, would we still need:
- A second-level, sub-set of local guidelines for Africa
- A third sub-level of guidelines for the East African Community (a group of countries which includes Tanzania)
- A fourth sub-level for Tanzania
- A fifth sub-level to reflect local conditions for Dar es Salaam, the capital of Tanzania ?
We can certainly find four or five levels of highway design guidelines in the USA, the UK and Australia. The trouble is many sub-level guidelines include details which are not “local”, but repetitions (or even contradictions) to geometric details in regional and national roads. There must be some level of geometric detail which is not local at all.
Examples of “local” design standards could be for unusual road types such as power tiller roads in Bhutan, and Lancashire CC (UK)’s “greenways”. One approach could be to argue
- that local differences affect streets (design speed at or below 70 km/hr) but not roads (design speeds above 70 km/hr).
- That for roads (design speeds above 70 km/hr) all multi-country, national and regional standards could be replaced by one global set of standards / design guidelines
- That all standards should have the same, modular structure so that users can easily see what alternative values are being suggested in the different documents.
726 – UNECE “Trans European Motorway standards and recommended practice third edition”, Poland 2002
756 – UNESCAP, “Asian Highway Handbook”; United Nations, New York 2003
771 – SATCC “Draft code of practice for the geometric design of trunk roads”, CSIR, South Africa 2001