Road classification in Tanzania

Before 1989

The Tanzanian manual on the “Geometric design of roads” published in 1989 refers to an existing road classification. It says the existing classification “takes into account and is in accordance with administrative  considerations and functional role of the roads”. The classification is

  1. Trunk roads
  2. Local main roads
  3. Regional roads
  4. District roads
  5. Unclassified roads

1989 classification

The 1989 manual goes on to propose, for design purposes, six categories of road:

  1. Trunk roads
  2. Regional roads (inter-regional)
  3. Regional roads (inter-district)
  4. District roads
  5. Major feeder roads
  6. Minor feeder roads

2007 classification

The Tanzania Road Act of 2007 in part III, section 12 introduces a new classification of roads. This groups the public road network into national roads and district roads, with the further classification (summarised) as follows:

Tanzania 01

2011 classification

A new Tanzanian “road geometric design manual” was prepared by Tanroads, the MPW, and the Norwegian Public Roads Administration. Experts from these organisations formed a Working Group, which acknowledged the “use of valuable information from corresponding manuals in the neighbouring countries.  Particularly the Geometric Design Manual of Uganda was of great value in developing this Manual”.

The 2011 road geometric design manual refers to two types of road classification

  • Administrative and functional classification
  • Road design classification

 For the administrative and functional classification the existing network is classified in accordance with the Road Act of 2007 (see above), although slightly re-numbered, and with the same five main classes:

Tanzania 02

Road design classes

The  2011 road geometric design manual defines a set of road design classes. These are related to the administrative / functional classes in terms of design year AADT (ref. 294 table 2.2). The document says “Any new road to be designed shall be selected from these design classes”. There are specified cross-section widths and surface types for each design class. The design classes are also related to (for example):

  • Administrative classification
  • Design year AADT
  • Level of access control
  • Design speed
  • Terrain
  • Carriageway width

Opinion

  • It is not clear that the accepted road classification covers all roads. The Road Act 2007 says its classification is for public roads, and there seems to be little reference to village streets or to the local urban road network.
  • The 2011 road geometric design manual has some loose terminology: for example there are references to a road hierarchy and a functional road hierarchy but no definitions for them. There is a definition for a network hierarchy, but this then refers to a classification of roads (with only two classes, national and district roads)
  • The 2011 manual has a clear layout and structure, making it easy to read and understand (manuals from some other countries could usefully adopt a similar structure)
  • The manual also seems to suggest that Tanzania (population 45 million) can live with a road network which has only 8 different road types. New Zealand’s NZS 4404 : 2010 has more than this just for urban and rural roads. (I wonder if Norway (population 5 million) has just 8 different road types?).

References / sources

  • 294 – Tanzania, Road Geometric Design Manual (2011 ed.)
  • 298 – Tanzania Geometric design of roads, Manual 1989
  • 303 – Tanzania Roads Act 2007
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About roadnotes

Robert Bartlett is an international consultant with over 30 years of professional experience as a highway and traffic engineer with leading companies and organisations in several countries, including Germany, China (Hong Kong), Qatar and the UK. Specialised in urban studies, transport and the use of GIS, research has included new ideas on subjects such as the study of social justice using GIS, the dimensions of vehicles, and comparative geometrics (highways and transport).
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