Is there a way to calculate how diligently Kenyan motorists change their car’s engine oil, and how often they do it? — PL
There may be several ways. But the quickest and cheapest way to get a general impression may be to compare total national fuel sales to total national motor oil sales in terms of quantity.
As a guess, if we collectively consume six million liters of fuel per day and 60,000 liters of engine oil (through fill-ups and full oil changes), the ratio would be 100:1.
You can then apply this to a normal car. Every time you change five litres of oil, a 100:1 ratio will consume 500 litres of fuel.
If its average fuel consumption is 13 km/h, it will travel 6,500 km with that amount of fuel. This indicates that it is making a reasonable effort.
If the ratio is closer to 200:1, the interval indicator would be an oil change every 13,000 km, which is bordering on dangerous negligence. If the ratio is 50:1, this indicates an oil change every 3,250 km, which is bordering on paranoia.
Given the large variation in fuel consumption between cars, and the large proportion of larger commercial vehicles including heavy trucks, this is far from an exact science.
The point here is that it is possible to get a general idea, in minutes and at no cost, by simply knowing something that is well-known (but not widely known) – the amount of gasoline sold and the amount of motor oil sold over a certain period of time. By doing this on a regular basis, the results will at least reveal “trends” (are we becoming more diligent or more careless).
Policy planners (and oil companies) are certainly doing this already, and we can assume that the results are not spectacular.
Otherwise, we would have seen massive public awareness campaigns, right? Choose your own emoji that matches this conclusion.
What to do with 60,000 litres of old motor oil a day (about 22 million litres a year – enough to fill thousands of Olympic-sized swimming pools) is a separate question.