Two Pints at Lunch
It is a Saturday. A rider has two pints of beer with lunch between 12:30 and 14:00. They weigh about 80 kg. They plan to ride home at 16:00, a 30-minute journey. They feel 'fine' and believe the alcohol has worn off. They have not eaten much besides the lunch. A friend offers them a lift, but they decline, saying they are under the limit.
1. Estimate the likely blood alcohol level at 16:00 and assess whether the rider should ride.
Read the worked answer
Rough estimate (illustrative, not a legal measurement):
- Two pints of average-strength beer (about 4.5% ABV) is roughly 4 units of alcohol.
- A common rough guide is that the body clears about one unit per hour. From 14:00 to 16:00 is two hours, so roughly two units may have been cleared, leaving about two units.
- For an 80 kg person, a very rough estimate might put blood alcohol around the lower legal limit or near it - but individual variation is large.
Key points:
- 'Under the limit' is not the same as 'fit to ride'. Even low levels of alcohol impair reaction time, balance, coordination, and judgement - the very skills motorcycling demands most.
- Feeling fine is unreliable - alcohol impairs the ability to judge your own impairment.
- Food, weight, and time affect absorption, but there is no reliable way for a rider to calculate their own level.
Advice: do not ride. Take the lift. The safe and legal choice is not to ride after drinking.
2. Explain how alcohol affects a motorcyclist specifically, and what the legal and personal consequences could be.
Read the worked answer
Effects relevant to motorcycling:
- Slower reactions - critical when a hazard appears suddenly.
- Impaired balance - a motorcycle is inherently unstable; balance is essential at low speed and in bends.
- Reduced coordination - clutch, brake, and throttle control degrade.
- Poor judgement - risk-taking increases and hazard perception decreases.
- Vision - reduced peripheral vision and slower adaptation to light changes.
- Fatigue - alcohol worsens tiredness.
Consequences:
- Legal: riding over the limit is an offence; penalties can include a fine, licence loss, and imprisonment. Refusing a test is also an offence.
- Insurance: may be invalidated, leaving the rider personally liable for damage.
- Personal: increased risk of a serious crash; a motorcycle offers little protection.
Conclusion: the only safe approach is not to drink and ride. Plan ahead - leave the bike, use public transport, or take the offered lift.