The effect of text messaging on driver behaviour

Organisation: RAC Foundation
Date uploaded: 15th July 2008
Date published/launched: Pre 2009

Texting behind the wheel impairs drivers’ reaction times by more than one-third (35%) according to a study carried out at the Transport Research Laboratory on behalf of the RAC Foundation.

Education campaigns have in recent years been developed to address this concern. New campaigns should be sure that they do not inadvertently encourage texting whilst driving. This can happen if activities, such as texting whilst driving, are presented as the ‘norm’.Carrying out the first UK research into the effects of texting while driving, the RAC Foundation and TRL used TRL’s driving simulator to research the effects of writing, reading and ignoring text messages on the driving skills of a test group of 17-24 year-old-motorists. In all key measures of driving performance, young people who were texting and driving were badly affected:

• Reaction times deteriorated by more than one-third (35%). This was worse than alcohol at the legal limit (12% slower) and driving under the influence of cannabis (21% slower).
• Drivers drifted out of their lane more often. Steering control was 91% worse, compared to 35% worse when under the influence of cannabis.
• The ability to maintain a safe following distance fell.

TRL’s experts concluded that “In real world traffic situations, it is suggested that poorer control of vehicle speed, lateral position, and increased reaction times in this situation would increase the likelihood of collision dramatically.”

All participants in the study described themselves as confident texters. Despite this, messages, which at a desk took an average of 22 seconds to compose, took on average 63 seconds when the texter was also driving. In one minute, a car travels half a mile at town centre speeds and over a mile at motorway speeds. During this minute, drivers are distracted in three ways:

• Mental workload: the work of composing the text takes the mind off the road.
• Control: using the phone’s keypad means that only one hand is on the wheel.
• Visual attention: eyes are on the phone not on the road ahead.

The key consequences found by the study were:-

• Slower reaction times: participants were asked to react to a buzzer or a visual cue which would appear on the screen of the simulator. Writing a text message had the biggest impact on reaction times, increasing them from 1.2 seconds to 1.6 seconds. At motorway speeds, this would mean travelling an additional three car lengths before beginning to brake. Some participants missed the visual trigger completely. TRL notes “the failure to detect hazards and increased response times to hazards has clear implications for safety”.

• Inability to maintain safe following distance: tailgating causes one-third of injury accidents on the motorway network. A safe following distance is vital to road safety. Participants were less able to maintain a safe distance behind a lead vehicle, and also strayed out of lane position behind it, when distracted by a texting task.

• Inability to hold lane position: participants’ tendency to drift out of their lane while trying to write a text increased by 91.4% compared to a ‘control drive’ where they were concentrating on the driving task. In busy dual carriageways and motorways, drifting out of position is a serious hazard, while in a town centre or rural road losing position might result in a collision with a pedestrian, cyclist or motorcyclist.

Comparing the level of distraction caused by texting to previous TRL studies into the impairment effects of drugs, alcohol (at the legal limit) and speaking on a mobile, the report concludes that texting had the greatest impact on lane positioning; and the second greatest impact on reaction times (second only to using a hand-held phone), making texting while driving as risky as other well-recognised risks such as driving while on drugs or under the influence of alcohol.

Despite the dangers, in a Facebook poll nearly half of UK drivers aged 18-24 admitted to using SMS while driving.

For more information contact:
Elizabeth Box
T: 020 7747 3448

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