Most countries have their own highway design standard or manual. However it is unlikely that the authors in start with a blank piece of paper, carry out their own detailed research, and then come up with a new paradigm on how roads should best be designed. Nor do the authors copy the whole of a design manual from another country, change the cover, and publish it as their own work. So, if we are being optimistic, any manual on highway geometrics will contain some original idea, some material taken from earlier publications, with perhaps some improvements on this earlier material as well.
To take some examples of building on earlier work:
The 2002 (?) update of REAM’s “A guide on geometric design of roads” (ref.1032) refers in its list of references, to Malaysian sources, and also to some UK and USA resources. The latter include reference to the AASHTO “A policy on the design of streets and highways” (1994 and 1973 editions).
Volume1 part II of Paraguay’s “Normas para la Evaluacion de Proyectos y Geometria Vial” (ref. 895) of 2011 ends with a bibliography. This suggests that the document is based on research and publications in other countries in South America. The bibliography includes references to the AASHTO guideline (1994 edition) and to South Africa’s “Geometric design guidelines”.
AFCAP series of country design standards for low-volume sealed roads
What seems to be a good example of the “building on earlier work” approach is the work funded by AFCAP. AFCAP (Africa Community Access Programme) is a UK government-funded programme of research, knowledge dissemination and training, designed to address the challenges of providing safe and sustainable access to poor communities in Africa. The programme is currently active in Ethiopia, Kenya, Ghana, Malawi, Mozambique, Tanzania, Zambia, South Africa, Democratic Republic of Congo and South Sudan and is developing relationships with a number of other countries and regional organisations across Africa.
One of the objectives of AFCAP is to operationalise the SADC (Southern Africa Development Community) Guideline for Low Volume Sealed Roads (LVSR) (ref. 1094). AFCAP project has led to a series of related documents which combine generally applicable design principles with adaptations to meet specific local circumstances. Examples include:
- Appropriate design standards for low volume sealed roads in Kenya (ref. 1094)
- Appropriate design standards for low volume sealed roads in South Sudan (based in part on the document for LVSR in Ethiopia) (ref. 1092)
- Malawi design manual for low volume sealed roads (ref.1098)
If you are interested in reading the AFCAP documents there is a webpage which lists them by country and region here.
There are problems associated with building a new standard on earlier work. Take for example the use of the AASHTO document referred to above. It has been revised and updated, with new editions being published in 2001 (4th edition), 2004 (5th edition) and 2011 (6th edition). In this case it could be argued that the Malaysia and the Paraguay documents werebased on an out-of-date version of the AASHTO document. It also suggests that whenever AASHTO updates its publication, the Malaysian and Paraguayan authorities are more or less obliged to produce an update of their standards as well.
Then there is a slight concern about the value of the AASHTO publication as a reliable source anyway. If the document was indeed good enough to be seen as “the” reference manual for highway design, why do so many US states produce highway design manuals of their own? (e.g. Texas roadway design manual (ref. 157), Oregon highway design manual (ref. 861) etc.
Finally there is the problem of redundancy. Many standards and reference works are, like the AASHTO publication, updated from timeto time. It it is not always easy to tell if a standard is still valid, or whether it has been superceded by another one (and if so, which). One example of good practice here is how website of Chile’s Ministry of Transport and Telecommunications gives an overview of the development of volume 3 of its highways manual (link):