Letter of the week

Each week, we will feature a letter we think is worth a second read.

Relook traffic lights and

signs with myopia in mind

With the recent accidents at major four-way traffic junctions, it may be timely to relook the design of traffic lights and road signs, with human limitations firmly in mind (NUS undergrad dies, 5 injured in accident at Clementi junction, April 21; and Woman, 23, dies after another road junction collision, April 23).

Take the junction of Clementi Road and Commonwealth Avenue West - the distance from the traffic light to the line where vehicles should stop is about 50m, according to Google Maps, and the size of the traffic light in use is about 20cm to 30cm in diameter.

As an optometrist, I would say that at that distance, the visual acuity required to see the traffic light would be 6/2.4 or 6/3.6, which exceeds the normal 6/6 vision of an ordinary person.

Moreover, it could be difficult to distinguish the arrow sign from the normal traffic light.

To make matters worse, many Singaporeans are myopic and may not be wearing the right corrective lenses. Being myopic will also lead to visual acuity being worse than 6/6, even with the best optical correction.

To further compound the situation, night vision deteriorates even more with night myopia and interfering glare.

The scenario does not include other factors, such as vehicles moving at about 50kmh and increased viewing angles.

The Land Transport Authority may need to redesign road signs and traffic lights, taking into account wider roads and the vision limitations of Singaporeans.

Adeline Yang (Ms)