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How dangerous is driving with a mobile phone? Benchmarking the impairment to alcohol


Research has shown that phone conversations while driving impair performance. It is difficult to quantify the risk of this impairment because the reference is usually made to normal driving without using a phone. 'Worse than normal driving' does not necessarily mean dangerous. There is a need to benchmark driving performance while using a mobile phone to a clearly dangerous level of performance. Driving with a blood alcohol level over the legal limit is an established danger. This study was designed to quantify the impairment from hands-free and hand-held phone conversations in relation to the decline in driving performance caused by alcohol impairment. The TRL Driving Simulator was used to provide a realistic driving task in a safe and controlled environment. Twenty healthy experienced drivers were tested in a balanced order on two separate occasions. The drivers were aged 21 to 45 years (mean = 32, SD = 7.8) and were split evenly by gender. Before starting the test drive, participants consumed a drink, which either contained alcohol or a similar looking and tasting placebo drink. The quantity of alcohol was determined from the participant's age and body mass using the adjusted Widmark Formula (the UK legal alcohol limit 80mg / 100ml). The test drive had four conditions: (1) motorway with moderate traffic, (2) car following, (3) curving road, and (4) dual carriageway with traffic lights. During each condition the drivers answered a standard set of questions and conversed with the experimenter over a mobile phone. The independent variables in this repeated measures study were normal driving, alcohol impaired driving, and driving while talking on hands-free or hand-held phone. Results showed a clear trend for significantly poorer driving performance (speed control and response time) when using a hand-held phone in comparison to the other conditions. The best performance was for normal driving without phone conversations. Hands-free was better than hand-held. Driving performance under the influence of alcohol was significantly worse than normal driving, yet better than driving while using a phone. Drivers also reported that it was easier to drive drunk than to drive while using a phone. It is concluded that driving behaviour is impaired more during a phone conversation than by having a blood alcohol level at the UK legal limit (80mg / 100ml). (A)

Author Burns, PC,Parkes, A,Burton, S,Smith, RK,Burch, D Pages 56
Date 01/01/2002 Reference TRL547
ISBN 1-84608-546-2 ISSN 0968-4107



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