Hyderabad: Given the pathetic state of roads in most cities across the country, the findings of a study done by Nitin Baburao Shelke, an M.Tech student of the mechanical engineering department of the Indian Institute of Technology-Hyderabad, may be of help to motorists. To reduce stress on one’s body, Mr Shelke’s research found, you should incline your seat to 10 degrees, reduce speed of your car and loosen the grip on the steering wheel when you approach a speed-breaker or a pot-hole. Those who are not driving should incline their seat to 60 degrees to reduce the impact further. Two-wheeler drivers should loosen their grip on the handlebars a little and decrease speed.
The state government authorities can do their bit by constructing speed-breakers that are inclined and flat on the top rather than ones that are rounded on top or shaped like mounds. All these measures will help motorists avoid pain in the lower back due to the sudden jerks caused by speed-breakers and other obstructions, according to Mr Shelke’s research. The International Standards Organisation has developed ISO 2631-5:2004 standard for evaluating effects on the human body due to vibrations and continuing shocks from the road.
This can be expressed in terms of Daily Equivalent Static Compression Dose which should be less than 0.5 Mega Pascals (MPa) so that there is no adverse impact on the lumbar spine. While 0.5-0.8MPa will have moderate impact, more than 0.8MPa will have adverse impact. Mr Shelke calculated the Daily Equivalent Static Compression Dose using computer models for speed-breakers with flat and rounded tops. In each of these tests, it was found that inclining seat and lowering speed reduced the impact of sudden jerks to less than, or equal to, 0.5MPa.
The human body has six joints: head and neck, upper leg, lower leg, arm, forearm and the thorax that consist of the vertebral column, including the lower back. Force was measured on these six joints when the grip on the steering wheel is loosened and tightened. It was found that loosening grip had reduced impact on the joints.
