Should we be concerned about alcohol in bicycle crashes?

Narelle Haworth and Amy SchrammICADTS 2010, Norway 22-26 August 2010

Outline

• Background

• Factors potentially affecting alcohol involvement

• Data availability issues

• Research setting

• Analyses of crash data

• Conclusions

Background

• Alcohol in injured riders associated with– severity of outcome– not wearing helmets– riding at night– adult riders– hospital studies, rather than Police data

• Driver alcohol sometimes more common than rider in bicycle crashes

Factors potentially increasing alcohol-related cycling crashes

• Growth in size and diversity of cycling population– More adults– Cycling as the new golf– Hung-over commuters– Drink drivers who have lost licence

• Balance and coordination demands of riding• Not illegal or perceived lack of enforcement

Factors potentially decreasing alcohol-related cycling crashes

• Restricted overlap of riding and drinking patterns– by age group

• half of hospitalised riders are children– by time of day

• peaks 6-10 am and 2-6 pm for bicycle-MV crashes (Watson & Cameron, 2006)

– by day of week • weekday pattern of bicycle crashes (Watson & Cameron, 2006)

• Balance and coordination demands of riding– not ride if feeling affected?

• Factors affecting official data– less likely to report alcohol crash to Police?

Under-reporting of bicycle injuries

• International research– 13% of bicycle crashes appear in official crash

records in Norway (Veisten et al, 2007)

– 11% in US data (Stutts et al, 1990)

• Australian research– 3.5% of on-road cycling injuries reported to Police

(Hendrie & Ryan, 1994)

• Under-reporting greater for SV crashes and lower levels of severity

• How accurate is hospital data?

Cycling in Queensland

Analysis of crash data

• 7,293 Police-reported bicycle crashes Queensland 2003-2007

• Crashes on public roads only

• Contributing factors for unit at fault only– “under the influence”– “over the prescribed BAC limit” – missing is a mixture of none and not known

Characteristics of Police-reported bicycle crashes

• 94% bicycle-motor vehicle crashes, 4.5% single bicycle• Severity

– fatality 1%– hospitalisation 35%– medical treatment 41%– minor injury 23%– non-injury <1%

• Most crashes occurred 6-9 am and 3-6 pm • About 30% of reported crashes involved riders aged

under 17 and so unlikely to be tested

% crashes where alcohol reported

Severity All crashes Fatal 20.0 Hospitalisation 3.4 Medical treatment

1.8

Minor injury 1.9 Non-injury 3.3 All severities 2.6 (7293)

% crashes where alcohol reported

Severity Rider in single bicycle

Rider in bicycle-motor

vehicle

Driver in bicycle-motor

vehicle Fatal 20.0 17.0 26.7 Hospitalisation 12.9 2.9 2.7 Medical treatment

5.6 1.9 1.5

Minor injury 6.8 2.5 1.2 Non-injury - 0.0 5.0 All severities 9.5 2.6 1.9 (327) (3058) (3771)

Alcohol by rider characteristics Rider at fault Driver at fault Gender Male 3.6% 1.9% Female 1.8% 1.8% Age group 0-16 0.2% 2.2% 17-20 4.2% 1.1% 21-29 7.5% 2.4% 30-39 7.9% 1.7% 40-49 7.0% 2.1% 50-59 7.9% 1.6% 60+ 2.8% 1.8% Helmet Yes 2.2% 1.7% No 7.6% 4.6% Unknown 8.2% 5.6%

Alcohol by crash characteristics

Rider at fault Driver at fault Day of week Weekday 2.4% 1.7% Weekend 4.0% 3.5% Lighting Day 1.8% 1.3% Dawn/dusk 4.6% 1.7% Dark 13.2% 6.4% Unknown 6.7% 0.0%

Summary

• Alcohol more common in– fatal crashes– male riders– non-helmeted riders– weekend crashes– night crashes

• Limitations– missing versus unknown– only riders and drivers at fault– no BAC levels– no off-road crashes

Conclusions

• Increase in cycling and vulnerability of cyclists support need to examine alcohol in bicycle crashes

• Driver alcohol contributes to alcohol in bicycle crashes• Alcohol contributes to injury by reducing helmet use• Improvements in data collection needed for firmer

conclusions• Need to improve legislation, enforcement and testing

Questions?

n.haworth@qut.edu.au

Mark your Diaries!International Council on Alcohol, Drugs and Traffic

Safety Conference (ICADTS T2013)August 2013, Brisbane Convention and Exhibition

Centre