Researchers at the Indian Institute of Technology-Bombay have found that a driver who is texting takes 40% longer to react than someone not using a phone, The Indian Express reported on Tuesday. When drivers indulged in complex texting, they took 204% longer to react.

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

The participants drove under five scenarios – without using a phone, while having a simple conversation over a phone like ‘Where did you go on your last trip’, while having complex conversations like solving arithmetic problems and puzzles, while texting messages of up to 10 characters, and while texting longer, complex messages.

The reaction time was measured in case of two situations – a pedestrian crossing the road and a parked vehicle making a sudden move.

“The situations were designed as simple and complex...,” Velaga told The Indian Express. “The reaction times were compared with that when the participant drove without a phone.”

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

“The main reason behind the increased reaction time while using phones is the reduced scanning of the roadway ahead, and thus a failure to notice sudden events which leads to a huge increment in the reaction time,” said Velaga. “The differences while texting and talking over the phone is that drivers can look at the road while talking and “notice the event earlier than while texting.”

Velaga said they knew that mobile phones distract drivers, but they wanted to “quantify the impact.” He explained that this was the first of a three-part series of studies on the distraction caused by cell phones.

“In the second part we have found that drivers, when talking on phone or texting while driving, incorporate compensatory measures such as slowing down,” said Valega. “The third part measures the lane deviations by drivers if they are on call or texting.”