Road traffic generation and distribution in the rural areas of Kenya

Abstract

This thesis contains a study of road traffic generati.on and distribution in the rural areas of Kenya. The economic development of Kenya, as with many of the less developed countries, gives priority to expansions in the rural sector. It is obviously desirable that these developments are complemented by those in the basic modes of transportation. This cannot be achieved on a rational basis unless there exists a factual knowledge of the traffic generation demands, goods and people, and the distribution patterns likely to result from the expected changes. Whilst Kenya may not be taken as a perfect model of the transport problems and traffic conditions in a less developed country it does exhibit many of the features that would be found in such a model if it existed. Thus it seems likely that some of the results may be applied to conditions outside Kenya. For instance, the results on the etficiency of the various forms of traffic distribution relationships would probably at least hold for road travel in East and Central Africa generally. The subject is one which has received considerable attention in the more developed countries but very little in,the less developed. However despite its intensive study there is in the literature widespread misunderstanding of what the terms traffic generation and distribution logically describe particularly in their mathematical formulationo The confusion is centered on the use by authors of the term traffic ge~e~ation to describe traffic components for which other more rational definitions already existo This situation necessitates the careful definition of each component of traffic in any study or analysiso The principle studies from which th« results for the analyses have been obtained were a national origin and destination survey of road traffic; a sample survey of the vehicle registration statistics for 1964; and the preliminary unpublished results of a 60-point road traffic census of Kenya -- designed for the Ministry of Workso In planning these studies intra-town activities were not considered~ but the influence of towns on traffic generation and distribution in the surrounding rural environment waso Also, as a consequence of the study planning and field surveys, it was found necessary to modify the methods traditionally usedo This was caused by the absence of regular commuter caused traffic patterns and by the low level of vehicle ownership which makes unpractical home-int~rview techniqueso As a result of these studies consideration has been given to the traffic generating and distribution characteristics of towns; some intra and inter year components of the time variation of traffic; the relationships governing the geographic distribution of vehicles; the form and efficiency of the relationships governing the spatial distribution of traffic around particular towns; the form and efficiency of the relationships governing the zonal interchange of traffic, and some aspects of the characteristic distribution of traffic. The results suggest that the basic mathematical forms developed elsewhere are applicable to conditions in Kenyao However the normal, non-experimental diff1culty of obtaining basic data on traffic, economic, agricultural and social activities places a constraint on the degree of sophistication that can be allowed in their use if practical planning tools are to resulto It was shown that much of the commonly used data for road planning was either not available in Kenya of inaccurately known. The latter is especially true of the vehicle licensing statistics. There are strong reasons for believing that there has been a fundamental error in the method of compiling official registration statistics since 1959. At present road traffic growth rates in Kenya are not known with any certainty and because of their importance in road planning a considerable effort was made to correct the vehicle licensing statistics in order to estimate indirectly the recent trends in traffic growth.