Data Analysis

A Theory on Formation of Potholes in Nairobi

A few weeks ago I was invited to provide data analysis assistance to the project  #whatisaroad – an initiative to map potholes in Nairobi and engage the county government on infrastructure through data. We set up a mapping party and I volunteered to cover Kayole and Buruburu Estates. Off with a pen, notebook and phone camera, I gathered information on a location of potholes, their sizes, directions, and landmarks. The first observations was that most potholes along Kayole Spine Road developed at junctions or intersections.

Intersection to Komarock at Step One stage
Intersection to Komarock at Step One stage

On this phenomenon, I got reminded of a concept in Systems Theory that states, ‘Systems expose vulnerabilities at points in which they interface with other modules’. As an example, a shirt begins to wear off from the sewn joints – a car wear off from connecting parts. Using the same analogy, it safe to conclude that the trunk road and the feeder roads are not built as a single continuum of asphalt  rather separately. Given great breaking force gets applied by cars when they approach junctions,  Shear Force pulls the two strata asunder much like continental plate tectonic movements . The conclusion is supported by the next set of observation that shows potholes developing at speed bumps. These ‘structures’ are normally built after road completion and great breaking force gets applied by cars at this points.

Pothole at a Bump in Kayole
Pothole at a Bump in Kayole

But herein is a third observation that shows bumps contributing to the development of potholes. These types of potholes manifest as ridges emanating from the speed bumps – prevalent in Buruburu and parts of Kayole. A perfect explanation for these potholes lies in Gilberts Tessellation –  a mathematical model built by Edgar Gilbert whom after being consumed by boredom decided to study how cracks form on dry mud and glasses. Turns out the cracks don’t form in a random pattern rather after an intial fault line develops the next crack is penpendicular to it.

Rabai Road Buruburu
Rabai Road Buruburu

We can avoid potholes by building all road sections as a single continuum! This not to forget that drainage is one of the major contributing factors to road degradation.

Got a pothole to report, or a road in desperate need of repair in Nairobi? Follow @whatisaroad & highlight yours using hashtag #WhatIsARoad . Remember to include a photo of the pothole with the road and closest landmark.

View the map of potholes in Nairobi here: https://whatisaroad.crowdmap.com/

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4 comments

  1. Hi,

    Two issues I would like to contribute Ute to your analysis,

    1. Most pot holes develop at intersections because of level differences.which turns them into pools when it rains. What we need is for the entire road network to be designed and treated as a single system.

    2. Bumps are built on top of the existing road & if you watch them being built no cutting is made. They contribute to road surface damage as they act as dam walls forming pools of water when it rains which then damage the underlying structure.

    Great initiative but would have been more effective if you utilised technology to a greater extend would have been great to see a pot hole map of Nairobi.

    Like

  2. How practical is it though? Building continuous sections might need a level of coordination that might not exist in this country,

    I get how braking and turning shear forces can cause potholes but shouldn’t this have already been factored in the initial design of the road? That’s what engineers are supposed to do no?

    Could the biggest problem we have be simply quality control during construction and lack of proper maintenance? I’ve noticed that period maintenance (carpeting, sealing etc) doesn’t happen till the local MCA has a funeral or the incumbent is looking for the next election’s votes, what if the responsible parties actually did their work and serviced the roads as should be done?

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    1. I believe we can invest in building continuous sections – our Chinese brother can assists us. They are already in town.

      Quality control may be a factor and I suspect maintenance creates further problems by patching segments of the road.

      Like

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