Can you read car registration plates from 22.86m?

By MUNGAI KIHANYA

The Sunday Nation

Nairobi,

11 July 2021

I believe that poor eyesight is one of the major causes of motor vehicle accidents in Kenya. I estimate that about one in every seven adults in this country wears sight correction spectacles, but, curiously, I have never seen a matatu driver wearing glasses! This makes me wonder: are they carefully selected from a special breed of people that have perfect vision?

I think that checking the eyesight of all drivers regularly – perhaps annually – would go a long way in reducing the number of accidents on our roads. Unfortunately, this check is done only once at the point of applying for a learner’s licence but not with any seriousness. It comes as a simple question in the application: “Can you read at a distance of 22.86 metres in good day light (with glasses if worn) a motor-car number plate containing six letters and numbers?”

When I saw that question, I wondered how they arrived at such an accurate distance: 22.86m. Not 20m. Not 25m. But 22.86m! This is a case of someone blindly converting from one system of units to another without thinking about the meaning of the numbers.

In this instance, the conversion was done from the imperial to the metric standard. Long ago, Kenya used to use inches, feet, yards and miles for measuring lengths and distances. In those days, the question asked was if you can read the registration plates from a distance of 75 feet. Then, when we migrated to metric units, the authorities simply multiplied 75ft by 30.48cm to get 2,286cm which is 22.86m.

This is ridiculous, to say the least! Optometry (the occupation of measuring eyesight, prescribing corrective lenses, and detecting eye disease) is not an exact science. There is a lot of room for approximation. Even the 75-foot distance of the original question was itself an approximation.

Indeed, in the old days, when driving exams were a more serious affair, the examiner would ask the learner driver to read the registration plate of a car in the police station parking lot – one that he’d guessed to be about 75ft away. The was neither a measured nor estimated distance; it was a simple guess!

Now, this regulation was obviously inherited from the British colonial government. Britain also migrated from their imperial measurements to the metric system. Today, their question reads: “can you read the number plate of a car from 20m away?”. Clearly, we are a long distance from catching up with them!