Phone use slows down drivers’ reaction by up to 204 per cent, reveals IIT-Bombay study

Participants were made to drive a stretch of 3.5 km under five circumstances: once without using a phone; once while driving during a simple conversation over the phone; once driving while solving an arithmetic problem and logical puzzles; once while sending a simple text message; and finally driving while sending a longer text message. (Representational)

RESEARCHERS AT the Indian Institute of Technology, Bombay (IIT-B), have found out exactly how dangerous using a cell phone while driving can be. The study by the department of Civil Engineering, which measures the distraction that mobile phones cause to driving behaviour, found a significant increase — up to 204 per cent — in the reaction time of drivers if they were talking on phone or texting while driving.

This means, a driver, who is calling or texting, may react up to four times slower to a change on the road as compared to a driver refraining from cell phone use.

Nagendra Velaga, Associate Professor, Transportation Systems Engineering at the department of Civil Engineering and research scholar Pushpa Choudhary conducted a simulated test on 100 licensed drivers in Mumbai of three different age groups: young (below 30 years of age), mid-age (30 – 50 years) and old (above 50 years).

Participants were made to drive a stretch of 3.5 km under five circumstances: once without using a phone; once while driving during a simple conversation over the phone; once driving while solving an arithmetic problem and logical puzzles; once while sending a simple text message; and finally driving while sending a longer text message.

The reaction time was measured for two situations — a pedestrian crossing the road and a vehicle parked on the road making a sudden move. “The situations were designed as simple and complex — simple being cases in which the participants could talk on phone or text without having to apply their mind and complex being where they had to think about answers. The reaction times were compared with that when the participant drove without a phone,” Velaga told The Indian Express.

The study found that in case of a pedestrian crossing the road, drivers having a simple conversation took 40 per cent longer to react compared to those who did not use a phone. In case of complex texting, the reaction time was 204 per cent more. A similar spike in reaction time was noted in case of parked vehicles making sudden movements and crossing the road. A simple conversation caused a 48 per cent increase in reaction time and complex texting caused a 171 per cent increase.

“We know that mobile phones can cause distraction among drivers but we wanted to quantify the impact,” said Velaga.
This is one of a three-part series of studies by Velaga and Choudhary on the distraction caused by cell phones to drivers. “In the second part we have found that drivers, when talking on phone or texting while driving, incorporate compensatory measures such as slowing down. The third part measures the lane deviations by drivers if they are on call or texting,” said Velaga adding that the study was conducted on state highways.