Fieldwork Question: Which are more effective in promoting vehicular traffic flow in Nairobi: roundabouts or unregulated intersections?

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IB HL Geography

Internal Assessment

Field Study

Hanna Ewell

HL Geography

Mr. Lavender

May 21, 2012

[word count:2149]

Table of Contents:

A         Fieldwork question and geographical context                                page 3

B        Methods of investigation                                                         page 4

C        Data                                                                                 pages 5-7

D        Written analysis                                                                pages 5-8

E        Conclusion                                                                        page 9

F        Evaluation                                                                        page 10

Part A         Overview

Fieldwork Question:

Which are more effective in promoting vehicular traffic flow in Nairobi: roundabouts or unregulated intersections?

Hypothesis: At rush hour, the unregulated intersection will be severely blocked because people force their way through and nobody waiting their turn. Roundabouts, especially the United Nations Avenue/Ruaka Road one, will work more effectively, up to a certain level of traffic, after which the same problem will arise.

Geographic context:

Over the past few years, traffic in Nairobi, the capital of Kenya, has increased tremendously due to the rapid increase in the ownership of cars.  This has led to problems such as congestion, depletion of green space and noise largely contributing to the overwhelming swell in environmental and urban stress. Nairobi’s geography, which is made up of numerous crests and troughs, has made it very difficult to build convenient connecting roads in order to eliminate some of the congestion problems. A person who works in the city centre coming from outside of Nairobi, therefore, has a very long trip to work, which is mostly spent sitting in their car, wishing they had woken up a little earlier to escape the mess. Nairobi’s poorly designed infrastructure and lack of cooperation between politicians, largely because of corruption, only adds to the chaos.

Drawn from the syllabus section: Urban Environments, the field study compares various measures of congestion at two types of intersections, which are common in Nairobi, roundabouts and unregulated intersections, in order to establish their effectiveness. Both intersections are on important commuter routes and therefore allow for effective data collection. Cars using the roundabout on United Nations Avenue and Ruaka Road come in from two directions, both from the Runda residential area where it is located and from the outer suburbs such as Kiambu District, funneling towards United Nations Avenue on their way to work. The intersection at General Mathenge Drive and Peponi Road has cars regularly coming in from all four directions, as the Westlands area where it is located is a bottleneck on the way to downtown Nairobi. Traffic is one of the largest contributors to early-morning frustration and hence, urban stress.

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*Attached maps show Kenya, Nairobi and each area of study individually

Part B        Methods of investigation

Our class decided to all do the same field study in order to be able to gather results more quickly and efficiently. We split up into different groups at each station (A, B, C, and D) to observe and record flow rates and transit times, starting with the roundabout of Ruaka Road and United Nations Avenue. The first thing we did was measure 25 meters from the center of the roundabout out ...

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