I am not sure by what process someone decides that a highway design standard needs updating. Maybe it happens on a regular basis, perhaps every five years; or perhaps someone decides that there have been so many changes in design philosophy that a new standard is essential. Whatever the case, over recent years several countries have decided to update their standards.
For example, in 2013 the Afghanistan National Standards Authority issued a request for the preparation of new standards and regulations, and in 2011 Qatar announced the award for the updating of the Qatar highway design manual.
One question that arises is, whether any of these new standards offer anything new to the highway engineering community. As a brief check of this, details on side friction and horizontal radius have been extracted from recently updated standards for Nigeria, Tanzania, Georgia and Albania. These details are compared with benchmark figures taken from a national standard from Switzerland.
In 2013 the Road Sector Development Team of the Federal Ministry of Works, with the assistance of the consultants Royal HaskoningDHV, produced an update of the Nigeria’s Highway Manual. Part 1, volume I of the manual covers Geometric Design.
The Tanzania Ministry of Works introduced a new road geometric design manual in 2011. The development of the new manual was financed by the Tanzanian Government and prepared through technical co-operation between the Ministry of Works (MOW), the Tanzania National Roads Agency (TANROADS) and the Norwegian Public Roads Administration (NPRA).
Around 2007 the Spanish company EPTISA prepared a new highway design manual for Albania. The document was developed as part of an EU-funded project managed by the European Commission delegation to Albania. Document ARDM 2 covers the geometric design of roads.
As part of a World Bank project, new road design standards were prepared for Georgia and issued in 2009. It is believed these standards were prepared by a consulting company from Germany.
The Swiss organisation VSS (Association of Highway and Transportation Specialists) is involved in research and standardisation in the field of roads and transportation. One of its documents is VSS 640-080 which provides details on the basics of highway design (including details on side friction and horizontal radius).
Comparison of values for side friction and minimum horizontal radius
The values for Nigeria, Tanzania and Switzerland are very similar:
Minimum horizontal radius
The values for minimum horizontal radius are all very similar:
You could expect the values for side friction and minimum horizontal radius to be different between countries. After all, countries could expect to have different typical values for typical tyre wear or road surface condition; and countries might be expected to have different policies on factors of safety to be applied to either side friction or horizontal radius. But what the tables show are essentially the same sets of values .
Perhaps the various development teams did not make adequate background research for their country of interest; or perhaps, and at least for the design of main traffic routes, basic design details are always the same. In this case, it would be easier and cheaper for a country such as Tanzania to purchase a copy of the Swiss standards and issue local deviation notes where circumstances are so special to warrant it. After all, this would not set a precedent – the Republic of Ireland uses this approach in its adoption of UK highway design standards for main traffic routes. There would also be the advantage that the work on updating design standards would be carried out by the Swiss organisation, and there would be no need for Tanzania (Nigeria, Georgia , Albania) to carry out their own regular updates.
294 – Tanzania, “Road Geometric Design Manual (2011 ed)”, Ministry of Works, 2011
732 – Switzerland, “VSS 640-080 Projektierung, Grundlagen (basics of road design)”, VSS; 1991
1155 – Albania, “ARDM 2 Road design manual vol. 2 / geometric design”, MPWTT, 2007
1389 – Georgia, “SST Gzebi:2009 / Georgia road design standards”, LEPL; 2009
1505 – Nigeria, “Highway manual part 1 Design / vol. I: geometric design”, Federal Ministry of Works; 2013