The number of victims of single-bicycle accidents is substantial, and is continuing to rise. A&E departments currently treat 46,000 injuries sustained in single-bicycle accidents each year. Of these, approximately 6,000 victims are admitted to hospital. An estimated 50 people die each year in single-bicycle accidents. Given these numbers, single-bicycle accidents entail significant medical costs as well. Research question Despite the scale of the problem, little research has been conducted into single-bicycle accidents. These accidents are rarely registered by the police, which makes it difficult to gather information about the causes of the accidents. Without insight into the causes, it is difficult to determine which measures would be effective in reducing the number of accidents. For this reason, the Research Centre for Transport and Navigation of the Ministry of Transport, Public Works and Water Management has commissioned the Dutch Consumer Safety Institute to study the following problem: 'What are the most important factors that cause single-bicycle accidents?' Research method A survey among bicycle accidents victims was conducted. All bicycle accident victims treated in an A&E Department in one of the thirteen LIS hospitals (hospitals that participate in the Dutch Injury Surveillance System, LIS) in the period from February 2008 to June 2008 were sent a questionnaire through the hospital. A total of 2,975 victims received a questionnaire within approximately two months after their treatment in the A&E Department. 1,142 of the questionnaires returned could be used for this study (a response rate of 38%). The analyses are based on 723 victims identified as the cyclist involved in a single -bicycle accident. In addition, the study also examined the answers provided by 61 passengers who required treatment in an A&E department after a single-bicycle accident. The Injury Surveillance System provided data for studying some of the characteristics of singlebicycle accidents. Characteristics of single-bicycle accidents Some characteristics of single-bicycle acci-dents were studied using the Injury Surveillance System, and then compared to the number of kilometres travelled by bicycle. By calculating the likelihood of a single-bicycle accident per kilometre travelled, we draw the following conclusions: • Children under the age of 12 and senior citizens over the age of 65 have an increased risk of being involved in a single-bicycle accident requiring treatment in an A&E Department. Only the elderly have an above-average risk of sustaining injuries requiring hospital admission due to a single-bicycle accident. • Up to the age of 55, men are more likely to be involved in a single-bicycle accident than women, while women are more likely accident victims after the age of 55. • At night and during the weekend, cyclists have an above-average risk of being involved in a single-bicycle accident. The periods with the highest risk for such accidents are weekend nights. Not all of the differences in risk levels can be explained in the context of this study. The differences between the age groups are probably largely due to the Increased vulnerability of the elderly and children's lack of cycling skills and experience. The elderly are more likely to sustain fractures as the result of a fall. The increased risk of accidents during weekend nights may be alcohol-related. The results of this study concur with this hypothesis. Eight percent of the victims indicated that they had drunk more than two glasses of alcohol before the accident occurred. In 20 out of the 28 accidents studied that occurred during weekend nights, the cyclist stated that he or she had consumed more than two glasses of alcohol before the accident. Factors involved in the occurrence of an accident. The study shows that the following factors play a role in the occurrence of single-bicycle accidents: • Almost half of all single-bicycle accidents occur in part due to the behaviour of the cyclist (awkward movements). Accidents are often the result of the cyclist making a steering error. In some cases, the accident is caused by the cyclist's feet slipping off the pedals or by awkward movements the cyclist makes to avoid other traffic. • In addition to the cyclist, the road surface is also a factor in the occurrence of single-bicycle accidents. Sometimes accidents are due to characteristics of the road that are difficult to influence or cannot be influenced at all, such as a wet, slippery surface. In other cases, the accident resulted from holes in the road, tyres getting caught between tram rails, tree roots or rubbish on the road. These characteristics can be dealt with2. • The behaviour of other persons plays a part in single-bicycle accidents to a somewhat lesser degree. Although single-bicycle accidents do not involve collisions with other vehicles or pedestrians, other road users do play a role in the occurrence of falls or collisions with other objects on the part of the cyclists. For example, a cyclist may have to swerve to avoid another person, resulting in a fall or collision. • Alcohol use is a factor in many accidents that occur in the weekend, especially among the age group 20-54. • Bicycle defects contribute to accidents to a lesser extent: these defects can cause the cyclist to fall or collide with an object. These defects primarily involve parts that break down or defective brakes. • Distraction caused by mobile telephones and MP3 players is not a significant factor. Bicycle passengers are subject to distraction, but this Is primarily the result of them talking to others, looking around or focusing on other road users. • Lack of proper lights does not seem to play a large role in single-bicycle accidents, although it is an important factor in collisions with other road users. • Bicycle helmets are rarely used, with the exception of cyclists on racing bikes and mountain bikes, approximately half of whom wear a helmet. Are there differences between age groups or other groups of cyclists? • Age does play a role in the types of accidents cyclists are involved in. The youngest group is more likely to have a foot caught in the spokes than other age groups, both as a cyclist and as a passenger. Among teenagers (aged 13-19) other people's behaviour is a factor. Among the middle group (aged 20-54), bicycle defects play a part, while physical condition can be a contributing factor among senior citizens. • Among children up to the age of 12, cycling skills and experience probably play a role in the occurrence of accidents. • Those belonging to the groups up to the age of 19 are more likely to cycle with others in a group, and distractions such as talking to others and other people's behaviour can lead to accidents. • In the age group of 55 and over physical limitations probably play a larger part. Many accidents occur when mounting or dismounting the bicycle. Senior citizens also seem to be more easily distracted or frightened by other road users. This may cause them to swerve to avoid others or to make awkward movements, which may then result in a single-bicycle accident. We can also conclude that senior citizens often sustain serious injuries as a result of single-bicycle accidents: a quarter of the elderly victims were admitted to hospital after the accident. (Author/publisher)
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