A file photo shows a woman checks her mobile phone when driving. Sending text messages from your mobile phone while driving is more dangerous than climbing behind the wheel under the influence of drink or drugs, a study by Britain's Transport Research Laboratory (TRL) has found.

Sending text messages from your mobile phone while driving is more dangerous than climbing behind the wheel under the influence of drink or drugs, a study by Britain's Transport Research Laboratory (TRL) has found.

The reaction times of people texting as they drove fell by 35 percent, while those who had consumed the legal limit of alcohol, or taken cannabis, fell by 21 percent and 12 percent respectively, according to the study.

The study, which was commissioned by motoring group RAC Foundation, also found that the ability to stay in lanes or maintain a safe distance from the vehicle in front was worse than drivers under the influence of cannabis.

"This research demonstrates how dangerous it is to drive and text," TRL Senior Human Factors Researcher Nick Reed said in a statement.

He said drivers who texted were distracted by taking their hand off the wheel to use their phone, by trying to read small text on the phone display and by thinking about how to write their message.

"This combination of factors resulted in the impairments to reaction time and vehicle control that place the driver at a greater risk than having consumed alcohol to the legal limit for driving," Reed told reporters.

One conclusion researchers made about why texting is so dangerous is the length of time it takes to compose a message while driving.

The TRL said that composing a text message behind the wheel took 63 seconds, in which time a car travels half a mile within town centre speed limits and over a mile within motorway speed limits.

Nearly half of all 18-24 year-olds admitted to texting as they drove, a separate survey by the RAC Foundation discovered.

The TRL study selected 17 people from the 18-24 year-old age group to take part in a simulated road test, in which they were asked to read, write, and ignore texts on a variety of roads.

"The participants in this study were almost unanimous in their view that drink-driving was the most dangerous action on the road," RAC Director Stephen Glaister said.

He said the research clearly showed that a motorist who is texting is significantly more impaired than a motorist at the legal limit for alcohol.

"No responsible motorist would drink and drive," Glaister said in the statement. "We need to ensure that text devotees understand that texting is one of the most hazardous things that can be done while in charge of a motor car."