A study conducted by UN-Habitat, an analysis of the road pattern of Nairobi based on satellite images, shows the city has 23 different street patterns. One reason for traffic-congestion is that streets are not fully connected to its vicinities.
A second finding is the amount of land allocated to streets. For example, in central Nairobi, approximately 12 per cent of the land is allocated to streets. A functioning traffic system in a modern capital generally requires around 30 per cent of land allocated to streets. These two major findings lie at the heart of the traffic jam problem in Nairobi: Too many street patterns and too few streets that are adequately connected.
What’s critical is determining the type of intervention that will provide the most efficient results, considering the lack of financial resources available for wholesale transformations. For UN-Habitat, the first priority is the proper connectivity of the different street patterns.
An in-depth scientific approach based on traffic flow analysis demonstrates that the lack of connectivity between neighborhoods is a primary cause of traffic congestion. A much smaller investment than the amount lost due to traffic congestion in Nairobi (estimated at Sh37 million) if spent on better street connectivity would solve the congestion problem.
There is need to increase the percentage of space dedicated to streets – from 12 per cent to at least 25 to 30 per cent. This would result in a positive transformation of the current mobility pattern. An important factor is to ensure the required legal instruments to properly implement an urban plan are in place. It is only through a comprehensive urban plan and adequate urban legislation that we can achieve a significant improvement in the street fabric needed to ensure the smooth flow of traffic in Nairobi.
A third and highly relevant aspect is related to the costs of increasing the space dedicated to streets. This can be relatively high, for which a proper model of investments is required. The tradition in many cities for creating additional public space has been through expropriation. But a common problem with expropriation is that it requires large sums of money, which may often not be available, and often leads to time-consuming litigation.
Many countries address this problem through Land Readjustment. This is a legal instrument by which an urban plan establishes a clear definition of the street pattern, and the land to implement the street pattern foreseen is given to the public authority, in exchange for enhanced buildability rights to owners of the plots in the vicinity of the streets. Since a good street pattern increases the value of buildings in the vicinity, it is a win-win situation for the owners of the land, urban developers and local authorities.
The contribution of land for street pattern is financially compensated through means of development rights. Then, the means by which public land is acquired by the public sector is not monetary, but in terms of development or buildability rights. This methodology has been established around the world to address the problem of the scarcity of space for a functional street pattern. This can be implemented through legislation that allows for the introduction of Land Readjustment nationally, or Nairobi. There are therefore different options, including national legislation or metropolitan legislation, or even local legislation.
The issue of mobility must be addressed in an integrated manner, through urban planning, or it risks inducing skewed policies that may seem effective on the surface. Introducing new transport systems, like trams or other mass transit on their own, without considering the issues related to urban planning and land use plans, will not solve the basic problem and can, indeed, worsen congestion. It is therefore crucial to understand the need to address the fundamentals of urban planning that underpin an effective mobility system.
UN-Habitat recommends that due attention is given to the basics of comprehensive urban planning to avoid unnecessary or even counter-productive expenditures that will not improve traffic flow and may even worsen it.
Investment in streets and better connectivity would greatly increase the urban value generated in Nairobi, and therefore be attractive to investments.
Andre Dzikus is coordinator of the Urban Basic Services Branch at UN-Habitat, Nairobi