Extremely drunk men may still be able to ride a bike in relative safety, while women cannot, according to a study into the effects of alcohol on cycling conducted in Germany.
Published in the International Journal of Legal Medicine, the study, which was funded by the German Insurance Association and German Insurers Accident Research, was led by Dr Bruno Hartung of the University Clinic in Dusseldorf.
It found that while some men could still ride competently despite a high blood alcohol content, no woman was able to do so.
Among the reasons put forward as potential explanations are that men have less body fat than women, so females are more susceptible to the effects of alcohol, that men in general ride faster meaning their momentum helping them avoid obstacles more easily, and that irrespective of the influence of alcohol, women tend to be more respectful of other road users.
The study assessed 41 men and 37 women for their ability to ride a bike safely with various levels of alcohol in their bloodstream.
Subjects, aged between 18 and 53 in the case of the men and 18-43 for the women, were required to undertake a series of tests assessing their riding while sober, and then at various levels of blood alcohol content.
Those included riding straight ahead on a narrow, 45 metre track, riding while slaloming between poles placed 1.8 metres apart, riding clockwise around caps that decreased in space between them from 4 metres to 1.5 metres, and riding between movable plastic barrels spaced 1.2 metres apart.
Cognitive reaction was tested on their reaction to a manually adjustable traffic light and stop lines, or being presented with a memory test of a random word flashed on an LED display while cycling.
Special safety bicycles were used in the trials, which took place away from public roads, and participants wore motorcycle suits with additional elbow, knee and spine protectors, as well as a cycle helmet.
After getting used to the course by riding it sober, they then undertook it with various levels of alcohol in 0.3g/kg steps, with drinks available including beer, schnapps, red and white wine, vodka and rum.
Immediately before each round, they were subject to a medical examination including being breathalysed, and an ophthalmological test was administered afterwards. They were then given more to drink before moving onto the next step.
Demerit points were deducted from each infraction they made while riding, based on a scale that weighed the perceived severity of each mistake, split between “coordinative faults” and “cognitive faults.”
The former included leaving the track with both wheels or knocking over a barrel (3 points), difficulties starting riding or skipping an obstacle (2 points), or putting one or both feet on the ground for no reason (1 point).
In the latter group were faults such as riding through a red light (3 points) or a stop line (2 points) or being oblivious to the word shown on the LED display (1 point).
They were also tested on their ability to deal with a complex situation such as a ball rolling in front of them, a blocked path, the glare from a torch, and being subject to verbal disturbances.
For those, they were assessed on whether they had given an adequate or inadequate response, with 3 demerit points imposed for the latter.
The number of demerits committed in each individual’s ride when sober served as a benchmark for assessment of their subsequent rides.
Each of the women tested committed at least one severe fault once their blood alcohol levels were above 1.43g/kg, but beyond that threshold, six of the male subjects committed no severe fault at all.
Dr Hartung, who kindly supplied road.cc with a copy of the study, points out that a drunk cyclist is less of a danger to others than a drink driver.
Quoted on the Dutch website Vogelvrijefietser.nl he said: “I noticed during the study that only extreme drunkenness is very dangerous. Moreover, it’s always better to leave the car at home and take the bike instead, since it can cause less harm.
“In Germany there is a lot of debate about using alcohol and cycling. Many people think it shouldn’t be seen as a crime, and that you should get on a bike rather than in a car, but others believe drinking while cycling should be more strictly monitored.”
A further study led by Dr Hartung on cycling while hungover has just been published, so look out for a report on that here on road.cc soon.
In the UK, cycling while under the influence of drink or drugs is covered by section 30 (1) of the Road Traffic Act 1988, which says:
A person who, when riding a cycle on a road or other public place, is unfit to ride through drink or drugs (that is to say, is under the influence of drink or a drug to such an extent as to be incapable of having proper control of the cycle) is guilty of an offence.
Unlike driving a motor vehicle while under the influence of alcohol, however, there is no set threshold beyond which an offence is committed.
There’s a comprehensive analysis of the legal situation in the UK in this factsheet prepared by national cyclists’ charity, CTC.
Simon has been news editor at road.cc since 2009, reporting on 10 editions and counting of pro cycling’s biggest races such as the Tour de France, stories on issues including infrastructure and campaigning, and interviewing some of the biggest names in cycling. A law and languages graduate, published translator and former retail analyst, his background has proved invaluable in reporting on issues as diverse as cycling-related court cases, anti-doping investigations, and the bike industry. He splits his time between London and Cambridge, and loves taking his miniature schnauzer Elodie on adventures in the basket of her Elephant Bike.