On our battered city roads, how many inadvertent rides over bumps or potholes does it take before our back starts to groan?
A scientist from the National Aeronautical Laboratory (NAL) took up the challenge of finding out. After months of research, he concluded that if one is in an autorickshaw, just six are enough, while a car with a good suspension can ensure your back is protected until around 40 speed-bumps or 200 potholes.
Satish Chandra, Chief Scientist and Head of NAL’s Structural Technologies Division, sent dummies strapped with sensors on autorickshaw and car rides to see how the spine deals with the roads. “We are just aeronautic engineers. But, since we have the instruments, we thought of seeing how bad the roads are,” he says.
A contraption was made to calculate the forces acting on a human body, and this was placed in a car with good suspension and an autorickshaw. “The challenge of the experiment was to get auto drivers to go over potholes at high speeds,” says Mr. Chandra.
At a speed of just 25 kmph, the passenger in an auto starts to bear the brunt. Just six potholes are enough to cause discomfort to the spine. The acceleration of the head was found to be drastic, causing rotation of the neck. “With every 10kmph increase in speed, the gravitation force too increases by around three times. Here, going over just two or three potholes is enough to increase the possibility of chronic injuries,” said Mr. Chandra.
The study, he says, needs to be plotted on a map and advisories distributed among drivers. “For persons in the transportation business, and especially those using poorly maintained or older vehicles, there is a need to develop innovative ways to ensure these vibrations can be minimised,” says Mr. Chandra.