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February 21, 2019

Health at the roundabout

The word ‘traffic’ in its’ original meaning is associated with trade and commerce. It describes among other things the movement of vehicles, ships, persons and things in an area, along a street, through an air lane or over a water route. The origins of the word are disputed with some claiming that it is from mid 15th Century middle French ‘trafique’, others credit early 14th Century Italian ‘traffico’, while still others reckon it is from Arabic ‘traffaqa’ which means to walk along slowly together.

The ‘traffic jam’ is a 1917 American concept even though in 2013 it seems very Kenyan. Talk to arm chair experts and the roundabout - the circular intersection or junction through which road traffic is slowed and flows almost continuously in one direction around a central island to several exits onto the various intersecting roads- is often blamed for causing traffic jams. Yet the primary function of the roundabout is road safety.

A well-designed roundabout by slowing down traffic allows vehicles to change road direction relatively easily, while ensuring that pedestrians too can find a place to cross roads. A good pedestrian crossing should be set at least a car distance away from the edge of the entry or exit of the roundabout, ensuring that the driver can clearly see the persons on the road and is also moving slowly enough to come to a stop.

From a health and safety perspective you can envision a roundabout every 500 metres along the Mombasa-Malaba road and Thika highway. That would keep speed limits down and make trying to cross roads a safer life gamble. But it would also bring into question the main objective of building roads, which must surely be to ensure that ‘traffic’ in its original meaning takes place efficiently. If you take that meaning of traffic then you would conclude that the role of traffic police is to ensure that there is movement of persons and goods efficiently and safely. So why then are there so many traffic police stationed at roundabouts?

To answer this question we have to look at where traffic police are found. Many are found at various road blocks across roads in the country, some at designated truck inspection points, many at the major roundabouts in the city and a few hide themselves at strategic points to catch those motorists who enter or exit roads that are not meant to be entered or exited but are not clearly marked as such. Traffic in the city is already very slow; Ngong road for example averages less than 10 km/h most times, so road safety is not the primary issue at hand.

So the main reason why many police are found at roundabouts must be to speed up traffic, the assumption being that the roundabouts, despite the new countdown lights, do a really bad job of distributing vehicles. Despite all their efforts traffic jams in Nairobi are still among the worst in the world and there is a health and financial cost. The financial cost is plain to see, the health cost is deferred and so may not be apparent but still exists.

A vehicle at a standstill consumes more petrol than one cruising at steady speed. For every 60 seconds that an average well-serviced 1500 cc car is idling it consumes about two shillings worth of petrol. Sit in a traffic jam for two to three hours a day and you can see how you make oil companies happy. But if you then remember that about 60 per cent of traffic in Nairobi is pedestrian, that is people walking to and from work then you realize that not only does any traffic jam directly impact your pocket, but your vehicle also emit fumes that affect the health of a few hundred thousand Kenyans every single day.

Vehicles emit four major toxins. Carbon monoxide is emitted especially if the engine is not working efficiently and so does not burn the fuel completely. Hydrocarbons are pollutants that react with nitrogen oxide in the presence of sunlight to form ground level ozone hence creating smog. Nitrogen oxides are created when the fuel burning causes nitrogen and oxygen in the air to react with each other.

Nitrogen oxides affect the respiratory system leading to coughing and reduced lung capacity. Pity the smoker who walks to work. Lastly are particulate matter, soot and metals that are so fine, less than the diameter of human hair. These are the most serious threats are these fine particles are inhaled and lodge into the lungs where they can precipitate cancer in later years. The very young and those who already suffer from a lung disease, like asthmatics, are easily affected.

Roundabouts that are efficient not only prevent accidents from happening, they can also help prevent long term health problems, but only if they are allowed to work, and vehicles do not spend an eternity waiting to enter or exit a road. But if you are in a good vehicle, as any prophet preacher will tell you, thank God, at least your exposure to toxic pollution is limited. Consider the miracle of how the white on traffic police caps remain white with more than 1.2 million vehicles on Kenyan roads.

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