Alcohol consumption has long been known to increase the risks of crashes for all road users, including bike riders.
Driver impairment is now well understood and strict blood alcohol restrictions underpin driver regulation and licensing.
Bike riding is generally not similarly regulated. And it is common for those without a valid vehicle licence to continue to drink and ride a bike, possibly at less risk to others, but not to themselves.
With the rise in power assisted, and (illegally modified) power-driven bicycles, these blood alcohol exemptions may increasingly be questioned.
Although drinking is known to be statistically linked to increased bike crashes, little is known about how alcohol is causing these crashes: unlike car drivers, riders depend on factors such as balance and muscle control.
A new study in Sweden (where .02% is the limit for drivers) staged an experiment in which a group of riders was tested riding on a rolling surface in a simulated environment, after consuming measured amounts of alcohol, or none at all.
The researchers assessed factors such as stability, cognitive performance and riding ability as well as rider characteristics such as experience, fitness and rating for sensation-seeking personality.
The study confirmed that that alcohol intoxication affects bicycling stability, cognitive performance, and bicycling ability.
Bicycling stability and cognition was affected by intoxication in a similar way for all intoxicated participants.
Interestingly riders that rated their abilities and fitness as high did not consider that their ability to ride had been affected by alcohol, but it had.
Those that did not rate themselves fit or experienced did recognise their alcohol-induced limitations.
It is salutary that the most skilled, fit and risk-embracing of bike riders have great judgement of their limitations when sober, only to become the worst judge of their capabilities after a few drinks.
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