1. 16
Here are some Websites that you may find useful:
Think! Drink driving
http://www.dft.gov.uk/think/focusareas/driving/drinkdriving?
page=FAQ
Drink-driving and the law:
www.drinkdriving.org
NHS information on drink-driving:
http://www.nhs.uk/chq/
Pages/853.aspxCategoryID=87&SubCategoryID=871
Drinking and driving:
over the limit
How does alcohol affect
driving and why do we have
a drink-drive limit?

2. 2
What we cover in this booklet:
This resource is aimed at 14-18 year olds and for those who are completing
GCSE science.
Page no.
ALCOHOL
What happens when alcohol gets in to the body? 4-6
How much alcohol is in a drink? 6
How does alcohol affect the body? 7
How does alcohol affect driving? 8
THE DRINK-DRIVE LIMIT
What is the drink-drive limit in the UK? 9
What is Blood Alcohol Concentration? 9
How is Blood Alcohol Concentration measured? 9
What can affect Blood Alcohol Concentration? 10
WHY IS THERE A DRINK-DRIVE LIMIT?
Reasons for having a limit of zero 12
Reasons against having a limit of zero 13
QUIZ - TEST YOUR KNOWLEDGE! 14-15
15
Important points to take
away:
 Alcohol is a drug, and can have many effects on your
body and behaviour.
 Many of these effects can make driving dangerous.
 The drink-drive limit in the UK is 0.08% Blood Alcohol
Concentration (BAC).
 BAC is a measure of the volume of alcohol present in the
blood.
 Drinking the same amount of alcohol can affect people in
different ways: factors such as gender and body mass
can impact on blood alcohol concentration.
 It can be argued for these reasons that the drink-drive
limit should be zero.
 Countries that have a drink-drive limit of zero have not
been shown to have fewer road accident deaths than the
UK.
Answers to quiz questions:
1) The small intestine (75% of alcohol is absorbed form here).
2) 95% of alcohol is broken down in the liver.
3) Any three of: erratic behaviour, loss of co-ordination, reduced inhibitions, impaired
concentration, delayed reactions or increased self-confidence.
4) 0.08% BAC or 80mg of alcohol per 100ml of blood.
5) Any three of: gender, body fat, rate of absorption, rate of elimination, strength of
alcohol, rate of consumption.
6) Either: increased accidents due to dangerous driving or alcohol affects people in
varying amounts.
7) Either: foods/other products contain alcohol as well as alcoholic drinks or other
countries with a limit of zero do not have fewer road accidents than the UK.

3. 14
QUIZ - Test your knowledge!
Now you have finished the booklet, you should all be experts on
drink-driving, right?!
Complete the following questions to see how much you have
learnt...
1) Where in the body is the majority of alcohol absorbed
from?
______________________________________________
2) What percentage of alcohol is broken down in the liver?
______________________________________________
3) Name three effects of alcohol that may affect driving:
1. ____________________________________________
2. ____________________________________________
3. ____________________________________________
4) What is the legal drink-drive limit in the UK?
______________________________________________
5) Name three things that can affect blood alcohol
concentration:
1. ___________________________________________
2. ___________________________________________
3. ___________________________________________
6) Give one argument for making the drink-drive limit zero:
_____________________________________________
7) Give one argument against making the drink-drive limit
zero:
_____________________________________________
Now check your answers on the next page...
3
In 1998, 19% of fatal car crashes in the UK were related to
alcohol, and those aged under 34 years have the highest
rates of drink-driving.
(http://www.ukmotorists.com/drink%20driving%20explained.asp)
But what do we mean when we talk about ‘drink-driving’
or ‘driving under the influence’?
DEFINITION OF DRINK-DRIVING:
“ Operating a motor vehicle
whilst the volume of
alcohol in your blood is
above the legal limit”
MOTOR VEHICLE = doesn't just mean cars, but any type of trans-
port that has a motor, e.g. Motorbikes, go-karts, mobility scooters,
etc.
ALCOHOL = refers to ethanol, which is the type of alcohol found in
alcoholic drinks
LEGAL LIMIT = this is set by law, but may vary in different coun-
tries. In some countries this limit is zero!
Turn to the next page to learn more about alcohol and the body...

4. 4
What happens when alcohol gets in to
the body?
Well, firstly the alcohol needs to get in to the body:
ORAL INGESTION = eating and
drinking
Swallowed from mouth into
oesophagus and then reaches the
stomach.
After a normal meal, the stomach
takes 4-5 hours to empty into the small intestine
Once inside, alcohol needs to get into the blood:
Alcohol is absorbed mainly in the
small intestine, but also in the
mouth, throat and stomach.
Rate of absorption depends on:
**Quantity
(lots of alcohol = faster absorption)
**Strength
(stronger alcohol = faster
absorption)
**Food
(having lots of food in the stomach
= slower absorption)
http://health.allrefer.com/pictures-images/
stomach-and-small-intestine.html
Mouth
and
throat
Stomach
Small
Intestine
http://www.gutenberg.org/
files/18559/18559-h/18559-h.htm
INGESTION
ABSORPTION
13
Reasons AGAINST making the
drink-drive limit zero
The UK, USA and Canada have the highest drink drive limits,
allowing someone to drive with less than or equal to 0.08% blood
alcohol concentration.
Alcoholic drinks are not the only things that contain
alcohol!
Many foods do, including Christmas
pudding, sherry trifle and liqueur
chocolates. Some mouthwashes also
contain alcohol.
So your breath may contain traces of
alcohol on a breathalyser after eating or
even after brushing your teeth!
It may not decrease numbers of road traffic
accidents
Other countries, such as Hungary, have
a 0% BAC drink-drive limit.
However, the number of road traffic
accident deaths per number of people in
the population was actually more than
that in the UK!

5. 12
Reasons FOR making the
drink-drive limit zero
If alcohol can affect different people in so many ways, why is
drinking and driving not banned altogether?
Dangerous driving causing accidents
We know that drinking alcohol can
cause delayed reactions, loss of
co-ordination and reduced inhibitions;
all of which can increase your chances
of having an accident whilst driving a
vehicle.
If the drink-drive limit were zero then this risk would be eradicated
because driving after any alcohol would be banned.
Alcohol affects everyone differently
We discussed previously how
different factors can affect absorption
and elimination of alcohol, therefore
affecting blood alcohol concentration.
Given that there is huge variation in
different people (e.g. Weight, height,
gender, tolerance and other disease), how do we know that this
one limit is appropriate for everybody?
The answer is that we do not, the same amount of alcohol
consumed can have different effects on different people
5
DISTRIBUTION
Now that alcohol is in the blood it can move around the body:
Alcohol dissolves in water (it is hydrophilic),
it does not dissolve in fat
1 UNIT OF ALCOHOL REMAINS IN THE BLOOD FOR 1 HOUR
How many units of alcohol are in each of these drinks?
1) Large glass of wine 2) A pint of beer 3) An average cocktail
(answers at bottom of the page)
Now the body needs to get rid of the alcohol:
95% of alcohol is metabolised (broken
down) in the Liver into non-toxic
substances.
5% is eliminated without being broken
down the breath, urine, faeces and saliva.
What affects elimination of alcohol from the body?
 Rate of consumption - drinking more than 1 unit per hour =
build up of alcohol in the blood.
 Gender - women have more body fat = alcohol stays in blood
longer.
 Tolerance - heavy drinkers = body becomes used to clearing
alcohol and can do it more efficiently.
Answers to questions: 1)3 units, 2)2 units, 3) 4-5 units
METABOLISM AND
ELIMINATION

6. 6
Have you got all of that?!
Without looking at the previous pages, can you write down briefly
what happens to alcohol at each of the following stages:
_____________________________________
_____________________________________
_____________________________________
_____________________________________
____________________________________
____________________________________
____________________________________
____________________________________
__________________________________
__________________________________
__________________________________
__________________________________
_________________________________
_________________________________
_________________________________
_________________________________
Well done! Now check your answers on pages 4 and 5.
INGESTION
ABSORPTION
DISTRIBUTION
METABOLISM AND
ELIMINATION
11
Why is the drink drive limit not zero?
We have talked about how alcohol can affect you and your driving.
We know that a drink-drive limit is in place to stop this, and we
have looked at how the drink-drive limit is worked out.
In 2009, 17% of fatal road accidents were
caused by drink-driving
(http://think.direct.gov.uk/drink-driving.html)
So why do we have a drink-drive limit?
Why is it not just zero?
Can you write down reasons FOR making the drink-drive limit
zero, and reasons AGAINST doing this?
Please turn to the next page where we will look at reasons for and
against making the drink drive limit zero.
Reasons for Reasons against

7. 10
What can affect blood alcohol concentration?
We discussed previously some factors that affect elimination of
alcohol from the body, including gender and amount of body fat:
Alcohol is hydrophilic (binds to
water), but not to fat. The body
consists of fatty tissues and water
(blood is made up of mainly water).
Women naturally have more body fat
than men.
If a male and female of the same size and weight drink the same
amount of alcohol, who would have a higher blood alcohol
concentration?
The answer is the female: as you can see on the diagram, the
same amount of alcohol has a smaller amount of water to
dissolve in than it does in the male. In overweight/obese people
the same thing occurs, and they have a high blood alcohol
concentration.
What else can affect blood alcohol concentration?
 Rate of absorption
- This can depend on: food intake, amount and strength of
alcohol consumed and time between eating and drinking.
 Rate of elimination
- This can depend on: rate of consumption, tolerance to
alcohol and any liver disease
Can you explain why overweight
or obese people may reach
higher blood concentrations of
alcohol than thinner people?
Average man Average woman alcohol fat water
7
How does alcohol affect the body?
Can you name four effects that alcohol has on the body?
1) ______________________________
2) ______________________________
3) ______________________________
4) ______________________________
Now carry on reading to find out if you are right....
ALCOHOL IS A CENTRAL NERVOUS SYSTEM DEPRESSANT
(this means that it slows down activity in the brain)
Effects of alcohol include:
Can you think how these effects may influence driving ability, and
why might this be dangerous?
http://ifightthelaw.files.wordpress.com/2010/11/homer-drunk1.jpg
Slurred Speech
Reduced
Inhibitions
Loss of
co-ordination
Erratic behaviour
Impaired
concentration
Flushed
face
Increased self-
confidence and euphoria
Delayed
reactions

8. 8
How does alcohol affect driving?
Now that we know how alcohol affects the body, we can consider
how this can influence ability to drive:
Delayed reactions and impaired
concentration:
Your reaction time is how long it takes you to re-
act to something on the road (e.g. A person
walking in front of your car).
If you are travelling at 40 miles per hour and
your reaction time is delayed by one second, you
will travel an extra 17 metres before you press the brakes.
Increased self-confidence, erratic
behaviour and reduced inhibitions:
Increased confidence in your driving ability,
and a reduced inhibitions may cause you to
take more risks than you normally would
and ultimately lead to dangerous driving
that puts you and other road users at risk.
Loss of co-ordination
Driving requires use of your eyes, hands and feet all
at the same time! If you aren’t able to co-ordinate all
of these effectively you may struggle to maintain
control of the vehicle on the road.
Can you think of any other ways that driving could be affected?
9
What is the drink-drive limit in the UK?
The drink-drive limit is based on the volume of alcohol that is
present in your blood (aka the ‘Blood Alcohol Concentration)
Blood Alcohol Concentration (BAC) = the volume of alcohol
(in milligrams/mg) per 100 millilitres/ml of blood in the body.
The Legal Limit in the UK=
80mg of alcohol per 100ml of blood or 0.08% BAC
Translated into drinks this means that:
 Men can drink no more than 4 units before driving
 Women can drink no more than 3 units before driving
Can you remember how many units are in a pint of beer?
(check on page 5 if you need reminding!)
How is BAC Measured?
BLOOD
A sample of blood is taken from a vein and analysed
to work out how many milligrams of alcohol are
present per 100ml of blood. (Less than 80mg is below
the legal drink-drive limit)
BREATH
The police carry breathalyser machines that can
measure the amount of alcohol that is present on
someone’s breath (remember that small amounts
of alcohol are excreted in the breath without being
metabolised)
URINE
In a similar way to a breathalyser, the amount of un-metabolised
alcohol in the urine can help to predict the concentration of alcohol
in the blood.