Step 1. The big picture
In one sentence…
Risk factors are studied as a real cause of error: alcohol, drugs, speed, distraction, fatigue, adverse weather and overconfidence. In passenger cars on roads open to general traffic their effects tend to multiply, which is why the exam insists on anticipating and correcting before you lose control.
Step 2. The syllabus
2.1Alcohol and drugs
The law does not only penalise obvious intoxication: it also penalises exceeding the legal limits or driving with drugs present in your system.
- Novice drivers during their first two years, and certain professional transport drivers, have stricter alcohol limits than everyone else.
- Alcohol reduces attention, reflexes, vision and judgement even if the driver feels capable. In the exam, that false sense of security is often part of the trap.
- With drugs, don't focus the answer only on visible symptoms. Their presence in the body and the resulting impairment of ability make driving a punishable risk.
2.2Medication and psychophysical state
Medication that reduces reflexes, vision or attention requires reading the leaflet, avoiding driving where appropriate, and never offsetting the risk with overconfidence.
- Not all medicines affect you the same way, but the driver must check the warnings and act with caution. Responsibility does not disappear just because the treatment is legal.
- In exam questions, the correct option is usually to seek advice, read the instructions and not drive if there are effects that compromise control or alertness.
- Psychophysical state includes fatigue, illness, intense emotions and lack of rest. If they affect your attention, you must reduce risk or postpone the journey.
2.3Distraction at the wheel
Holding your phone, programming the sat nav while moving, or looking away from the road for a few seconds is enough to cover many metres blind.
- Distraction isn't always technological. Intense conversations, searching for objects, eating, smoking or looking at an incident also take your mind and eyes off driving.
- The exam often presents small distractions because they seem normal. The safe answer is to prepare before setting off and to stop if you need to handle something.
- A repeated distraction becomes a dangerous habit. If you don't see something in time, you can't apply priority, distance or signs, even if you know the rule.
2.4Speed and distance
Incorrect speed is not only exceeding the limit: it is also driving within the limit but without adapting your speed to rain, traffic, visibility or grip.
- Safe distance must allow you to stop without a collision, and it increases if the vehicle is heavy, articulated, two-wheeled, or driving in unfavourable conditions.
- The higher the speed, the less time to interpret signs and the more space you need to stop. That's why the DGT links speed, attention and distance in many questions.
- Don't use the vehicle in front as a fixed reference point to hug. Keeping a margin lets you spot braking, obstacles and other road users' mistakes without a sharp reaction.
2.5Fatigue and drowsiness
Drowsiness reduces alertness, lengthens reaction time and increases the chance of running off the road, rear-end collisions and lapses of concentration on monotonous routes.
- Warning signs are usually yawning, frequent blinking, involuntary changes in speed, difficulty remembering the last few kilometres and the need to correct your course.
- The only safe response to fatigue is to stop, rest and continue only once your control abilities have fully recovered.
- Opening the window, turning up the music or relying on habit does not fix drowsiness. In the exam, these apparent solutions are usually incorrect.
2.6Adverse weather
With rain, fog, ice, wind or glare, you must reduce speed, increase distance, smooth out your manoeuvres and use the correct lights from the first sign of risk.
- Weather changes grip and visibility at the same time. The risk isn't fixed just by turning on lights if you keep an inadequate speed or distance.
- Crosswind, a wet road surface or poor visibility require you to anticipate unexpected movements from other road users and avoid sharp turns, braking or acceleration.
- When the question mentions unfavourable conditions, look for answers that stack up caution: more margin, less abruptness, better visibility and constant attention.
2.7Preventive management
Risk perception improves when you anticipate junctions, pedestrians, vulnerable road users, merging traffic, school zones, roadworks and changes in grip before you reach them.
- Overconfidence appears when you mistake experience for invulnerability. Knowing how to drive does not cancel out alcohol, fatigue, phones, speed or bad weather.
- Before every journey, check whether you're fit to drive and whether the road demands more margin. This decision is also part of safe driving.
- In the B theory test, with 30 questions and a maximum of 3 errors, these topics pay off because they repeat in different scenes with the same preventive principle.
2.8Alcohol limits and boundaries
For most drivers, including an ordinary driver of a goods vehicle up to 3,500 kg, the legal threshold is 0.25 mg/l in exhaled air or 0.5 g/l in blood. During the first two years after obtaining the licence, it is 0.15 mg/l or 0.3 g/l.
- The lower threshold also applies to goods vehicles over 3,500 kg and to the listed passenger, public-service, school/children, dangerous-goods, emergency and special-transport services. The vehicle or service facts in the question matter.
- These are legal thresholds, not a safe alcohol allowance, and they are not calculated from drink units. Do not use a drink-to-BAC calculator to decide to drive: the safe decision is zero alcohol.
Step 3. Key points
If you only have a minute before the exam, revise this.
- 1.Identify risks that affect attention, vision or reaction time.
- 2.Don't drive under the influence of alcohol, drugs or incompatible medication.
- 3.Adapt speed and distance to your physical state, the road and grip.
- 4.Set up your phone, sat nav and belongings before setting off.
- 5.Stop at the first signs of drowsiness or fatigue.
- 6.Increase your margin in rain, fog, ice, wind or glare.
- 7.Don't normalise small, repeated distractions.
- 8.Question overconfidence even if you have experience.
Step 4. Exam traps
Mistakes the DGT uses again and again on this topic.
- Thinking that as long as you don't exceed the speed limit, you're always driving correctly.
- Reducing risk to alcohol alone and forgetting medication, fatigue or distraction.
- Believing experience removes the need to adapt distance and speed.
- Accepting false solutions against drowsiness, such as music, air or willpower.
- Handling the sat nav while moving because it seems like a brief action.
- Ignoring that unfavourable conditions require combining several preventive measures.
Step 5. Quick check
Four real exam questions on what you have just read.
Which circumstance related to vehicle ergonomics can encourage fatigue?
Step 6. Frequently asked questions about risk factors
- What can you do to avoid accidents caused by drowsiness or fatigue?
- Pay attention to the signs and symptoms of drowsiness and fatigue, and stop to rest. Recognise signs of drowsiness or fatigue and stop somewhere safe to rest. Plan regular breaks, as a guide every two hours or about 200 km, and sooner if symptoms appear. A break of a fixed duration does not guarantee restored driving ability: resume only when fit to drive. Do not try to compensate for sleepiness by speeding up or distracting yourself.See full question
- Drowsiness can occur while driving and cause an accident…
- If you have slept little or poorly. Insufficient or poor-quality sleep increases the risk of drowsiness, which can occur at any time, not only at night or after a meal. Maintain adequate sleep habits and plan breaks. If symptoms appear, stop somewhere safe and do not continue until fit to drive.See full question
- Which behaviour reduces the risk of hitting the vehicle ahead if it brakes suddenly?
- Keep a sufficient safety distance adapted to conditions. Keep enough distance to stop without colliding, adapted to speed, grip, visibility and braking ability. Increase the gap as conditions worsen. A rule of thumb in seconds does not replace that assessment or guarantee safety in every situation. If fatigued or drowsy, stop to rest; increasing the gap does not make you fit to drive.See full question
- Most vehicles are equipped with a cabin filter. Should it be replaced?
- Yes, under the manufacturer’s maintenance schedule and according to its condition. Yes, under the manufacturer’s maintenance schedule and according to its condition. The filter traps particles such as dust and pollen, and its capacity is limited; it does not automatically clean itself so as never to need replacement. Checking it before periods of greater pollen exposure may be useful, but there is no universal duty to replace it every six months or always at the start of spring.See full question
- Driving fatigue causes...
- the ability to concentrate and safety to decrease. Driving fatigue reduces the driver's ability to concentrate and their safety at the wheel. When we drive for many hours without resting, our performance gradually begins to decline, making driving increasingly dangerous without us hardly noticing. The effects of fatigue include the following changes: Reduced ability to concentrate: The driver becomes distracted more easily and more frequently. Reduced precision of movements: Movements become slower and less precise, increasing the number of errors made during manoeuvres. Vision and hearing problems: Vision can become blurred and hearing sensitivity can decrease. Physical discomfort: Increased feelings of heaviness, muscle stiffness, neck and back pain, migraines and cramps.See full question
Official sources
Test what you've studied on risk factors
Exam-style questions on this topic, with an explanation after every answer.
Now, practise it
Test what you have read with exam-style questions and an explanation after each answer.
Related lessons
- A1Risk factors
Risk factors are studied as a real cause of error: alcohol, drugs, speed, distraction, fatigue, adverse weather and overconfidence. On motorcycles their effects tend to multiply. Learn to recognise each factor and how the exam presents them so they don't catch you off guard.
- A2Risk factors
Risk factors are studied as a real cause of error: alcohol, drugs, speed, distraction, fatigue, adverse weather and overconfidence. On motorcycles their effects tend to multiply. Learn to recognise each factor and how the exam presents them so you're not caught off guard.
- AMRisk factors
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Efficient, environmentally sound driving reduces fuel consumption, emissions, wear and risk. The DGT studies it as a way of driving better, not just as a financial saving, and it must always be compatible with safety and the rules in force.
- BTraffic rules
Core topic for licence B: general rules of circulation, priority, speed, road position, manoeuvres, essential documentation and the punishable conduct most often asked about in the exam. Study it as practical decisions: who goes first, where you position yourself, when you must give way and how you reduce risk.
- BRoad safety
Road safety combines prevention, occupant protection and the correct reaction to an emergency. The theory exam usually mixes active safety, passive safety and the PAS response within the same question, so always study cause, consequence and safe conduct together.