Road Safety Research Report
Bicycle Crashes and Injuries
in Western Australia
The objectives of this study were (i) to examine current research into bicycle safety, and (ii) to analyse police and hospital data relating to bicycle crashes in Western Australia for the period from 1987 to 1996.
The rationale for undertaking the study was to determine the past and current status of bicycle safety in WA and provide information about the characteristics of bicycle crashes and injuries to use in developing bicycle safety initiatives
Five main areas of research were identified in the literature -
- Factors associated with bicycle crashes such as cyclist characteristics, crash circumstances, and temporal factors.
- The under-reporting of bicycle crashes in the police records which is evident when comparing police data with hospital and other sources of data relating to bicycle crashes and injuries.
- The extent of injuries to cyclists in terms of injury severity and body region of injury.
- Bicycle usage and traffic exposure, and the relative risk of cycling compared with other modes of transport.
- Measures to reduce bicycle crash and injury rates, which can be grouped into engineering countermeasures, vehicle safety features, education and enforcement.
Brief Review of Current Research on Bicycle Safety
A brief review of current research in each of these areas is provided in the report.
Data on bicycle crashes and injuries for the years from 1987 to 1996 were obtained from two sources, namely police reports and hospital admission records. Linked police and hospital data were used to examine the reporting rate to the police of road crashes involving cyclists admitted to hospital. The study used descriptive statistical methods to analyse these different data sources.
Summary of Major Findings
Police-reported Road Crash Data
Size of the Problem
- The number of bicycle crashes reported to the police in Western Australia decreased from 1,011 in 1987 to 718 in 1996. Over this period, the share of bicycle crashes as a percentage of all reported crashes decreased from 2.5% to 1.7%.
- The majority of cyclists involved in police-reported crashes were young and predominantly male.
- Cyclists involved in crashes were relatively younger than other road users involved in road crashes.
- Male cyclists in the 13 to 16 year age group had the highest rate of crash involvement, followed by males in the 17 to 24 year age group and males in the 25 to 39 year age group.
- Each year from 1987 to 1996, an average of seven cyclists were killed in road crashes, 140 were reported to have been admitted to hospital, 340 required medical attention, 90 were injured but did not require treatment, and 280 were involved in property damage only crashes or crashes of unknown severity.
- In 1996, helmet wearing status was unknown for 64% of cyclists involved in police-reported crashes, 26% were known to have been wearing a helmet, and 10% were known not to have been wearing a helmet. This implies a helmet-wearing rate of 72% for cyclists whose helmet wearing status was known.
Other Vehicle Characteristics
- Most bicycle crashes (96%) reported to the police involved a cyclist and at least one other vehicle.
- Right-angled crashes and sideswipe same direction crashes accounted for almost 60% of all police-reported bicycle crashes.
- The proportion of sideswipe same direction crashes as a percentage of all crashes decreased over the 10-year period, while in recent years the proportion of indirect right-angled crashes has also decreased.
- Right-angled crashes, rear end crashes, sideswipe same direction crashes and sideswipe opposite direction crashes accounted for 88% of all fatalities and 70% of police-reported hospital admissions. Indirect right-angled crashes accounted for 11% of hospital admissions.
- Over the 10-year period, 71% of bicycle crashes occurred where there were no traffic signs or controls, 13% where there were stop signs, 10% where there were traffic lights and 4% where there were give way signs.
- In recent years, relatively fewer crashes occurred at stop signs and relatively more at give way signs.
- The majority (95%) of police-reported crashes occurred on-road. Eighty-five percent occurred on urban-arterial and local roads, 12% on highways and 3% on main roads.
- Using the (pre-Delta) police regions, 83% of police-reported crashes occurred in the Perth region, 7% in the Fremantle region and 2% in the Midland region.
- Using the Main Roads WA regions, 84% of police-reported crashes occurred in the Perth metropolitan region, 7% in the South West, and 2% in each of the Goldfields-Esperance region and the Great Southern region.
- The peak times for bicycle crashes were 6am to 9am and 3pm to 6pm. There were differences in the distribution of crashes by time of day for different age groups.
- Weekend crashes had a different time distribution to weekday crashes with proportionately more weekend crashes in the 9am to 12 noon period and 12pm to 3pm period.
Hospital Admissions Data
Size of the Problem
- Each year between 1987 and 1996, about 650 cyclists were admitted to hospital with injuries resulting from road crashes. While the number of these hospital admissions has fluctuated on a year-to-year basis, there has been no trend over the period.
- Over the 10-year period, hospital admissions of cyclists as a percentage of all road crash casualties varied between 12% and 16%.
- The majority of cyclists admitted to hospital were young and predominantly male. Fifty percent of cyclist casualties were young males aged 16 years or less and 18% were young females aged 16 years or less.
- Compared with other road users, cyclists admitted to hospital were relatively younger. Sixty-eight percent of cyclists admitted to hospital were 16 years or less, compared with 32% of pedestrians and 13% of other road users.
- Young males in the 13 to 16 year age group and the 6 to 12 year age group had the highest rates of hospital admission.
- Injury severity was coded using the Abbreviated Injury Scale (AIS). According to this scale, each year in WA approximately four cyclists were admitted to hospital with critical injuries (AIS=5), 13 with severe injuries (AIS=4), 60 with serious injuries (AIS=3), 380 with moderate injuries (AIS=2) and 110 with minor injuries (AIS=1).
- Cyclists had fewer critical, severe and serious injuries (13%) compared with pedestrians (33%), motorcyclists (26%) and motor vehicle occupants (26%).
Body Region of Injury
- The most frequently occurring injuries to cyclists were head injuries (27%) and upper extremity injuries (27%), followed by external injuries (17%) and injuries to the lower extremities (14%).
- Injuries to the upper extremities have shown an almost steady increase from 17% of all cyclist injuries in 1988 to 31% in 1996.
- Head injuries accounted for the highest proportion of critical injuries (73%) and severe injuries (86%) to cyclists. Injuries to the lower extremities accounted for almost half of all serious injuries.
Common Injury Types
- Injuries were also classified by common injury type. The common injury types that cyclists sustained most frequently were head injuries (25%), open wounds (22%), upper limb fractures (21%), bruises and abrasions (14%) and lower limb fractures (10%).
- Head injuries were the most common injury type until 1991, but in recent years the proportion of head injuries has decreased and the most common injury types were upper limb fractures and open wounds.
Length of Stay in Hospital
- The majority of cyclists (55%) spent only one day in hospital, while 34% spent between two and seven days in hospital. The length of hospital stay has decreased over the period.
- Younger cyclists had shorter lengths of stay in hospital than adult cyclists.
- The injuries requiring longer stays in hospital were those to the lower extremities, the head and the spine. Cyclists who stayed in hospital for only one day had mainly head injuries (33%), upper extremity injuries (33%) and external injuries (16%).
- Most bicycle crashes (81%) resulting in a hospital admission were non-motor vehicle crashes (i.e., did not involve a collision with a motor vehicle).
- Fifty-one percent of bicycle crashes resulting in a cyclist casualty being admitted to hospital occurred on-road, 46% occurred off-road, and the place of occurrence was unknown for the remainder.
- Almost all bicycle crashes involving collisions with motor vehicles (95%) occurred on-road, while only 41% of non-motor vehicle crashes occurred on-road.
Place of Residence of Cyclist
- Seventy-three percent of cyclists admitted to hospital with road injuries lived in the metropolitan region.
Reporting Rate to the Police of Crashes Involving Hospital Admissions
- The number of cyclists recorded as being hospitalised in the police data was 23% of the number actually admitted to hospital over this period.
- The number of cyclists recorded as being hospitalised in the police data was 36% of the number actually admitted to hospital who were recorded in the hospital data as having had their crash on-road.
- Over the 10-year period, between 17% and 25% of hospital records had a matching (linked) police record.
- The linkage rate of hospital records to a police report was lower for cyclists than for pedestrians and other road users.
- In general, the linkage rate of hospital records to a police record was higher for cyclists living in the metropolitan region, for males, for older cyclists and for those with longer stays in hospital.
The results of this study were found to be generally consistent with other Australian and international studies in terms of the findings relating to the profile of cyclists, crash characteristics, injury severity and the most common types of injury. The majority of cyclists involved in crashes were young and predominantly male. With regard to crash circumstances, almost all police-reported bicycle crashes involved a motor vehicle and occurred on-road, while a high proportion of cyclists admitted to hospital following a bicycle crash were involved in crashes not involving a motor vehicle with only half occurring on-road. In the police data, the most common crash types resulting in fatalities or hospital admissions were right-angled crashes, rear end crashes and sideswipe crashes. Most cyclists admitted to hospital had moderate or minor injuries, with the most frequently occurring injuries being those to the head and upper extremities.
Some important differences were found in the information obtained from the police-reported data and the hospital admissions data. These were -
- Hospitalised cyclists were considerably younger than cyclists in the police-reported data.
- The two data sources revealed very different distributions across road user groups. The police data showed cyclists accounting for a much smaller share of road casualties, and motorists for a much greater share, than the hospital data.
- The number of cyclists involved in crashes in the police data decreased between 1987 and 1996, while the hospital data showed no downward trend in injuries to cyclists (although there were fluctuations on a year-to-year basis).
This report has important implications for the development of bicycle safety policy in Western Australia. The descriptive data - relating to the size of the bicycle safety problem, cyclist characteristics, injury details and crash characteristics - provide information that can be used to identify the crash and injury problem and develop strategies and programs for bicycle safety. In addition, the report has found some important differences between the police and hospital data that need to be recognised when decisions relating to bicycle safety issues are being made.