Written: Vinod Vasudevan & team Department of Civil Engineering, IIT Kanpur
BICYCLING IS being promoted globally for short-distance travel because of its eco-friendly nature. In Europe, most cities have dedicated bicycle lanes and a growing number of people are adopting cycling as their preferred means of transport. In India, we have had a good culture of cycling but that has not been because of health or environment reasons. Rather, it is because, for most cyclists in India, the bicycle happens to be the only vehicle they can afford. The bicycle is also popular among students for going to school or college, but it is fast getting replaced with one form of motorised transport or the other.
In recent years, there has been a growing interest among youngsters in urban areas to take to cycling. However, there are several barriers to adopting cycling as a mode of transport in bigger cities. Poor quality of roads, lack of dedicated lanes, and badly managed traffic are the very obvious barriers. I had carried out a study with my student Samyajit Basu in Delhi, Kanpur and Kolkata a couple of years ago to know what would make people start using bicycles. Almost 90 per cent of the respondents told us they would ride a bicycle instead of drive their motorised vehicles if there was a dedicated lane.
But even a modest speed hump can be a major barrier to people adopting cycling, as my more recent study with Tanuj Patel, a postgraduate student, has shown. Speed humps, which are quite common in India, are meant to slow down speed by inducing vibrations to the vehicle. There have been many studies, mainly in Europe, to assess the discomfort caused to motorists because of these vibrations, and these studies have been used to design the optimum speed humps.
In India, in spite of guidelines being in place, speed humps are designed in a random manner. No study has ever been done on the discomfort these speed humps cause to cyclists. This is what we have tried to do in our study. We carried out our experiments on the campus of IIT Kanpur, which has quite a few speed humps. It is important to note that at IIT Kanpur, students are not allowed to use motorised vehicles on the campus.
We measured the vibrations that these humps were causing to the body of cyclist by attaching accelerometers at three places — handle, seat and at the neck of the bicyclist. We then compared these with vibrations caused to the rider of a two-wheel, motorised vehicle travelling at the same speed. We repeated the experiments at speed humps with different geometry and at different speeds. There is a standard mathematical way to convert these kinds of vibrations into discomfort caused to the rider. Our results show that the discomfort caused to a cyclist was considerably higher than to the rider of a two-wheeler at the same speed, by a factor of two or more. Other studies have shown that the discomfort caused on a two-wheeler is much more than that in a four-wheeler.
What our study shows is that the rather innocuous looking speed humps, randomly designed, could also be one of the big reasons that prevent people from using bicycles in urban spaces. Therefore, if we are to encourage people to ride bicycles, we would need to address this problem. We are now looking at ways to improve the design of speed humps so that it becomes more bicycle-friendly. In the next six months or a year, we hope to come up with such a design.