Why 30 questions and why 3 errors
The 30-question format for the B licence was introduced to replace the older 40-question / 4-error test. The change had two goals: make the exam more representative of the official bank (30 well-distributed questions cover every block without redundancy) and indirectly tighten the bar — a 3-out-of-30 margin is 90 %, the same headline percentage as before but with less real wiggle room for silly mistakes. In practice the exam is statistically a bit harder than the old 40-question format.
For the professional permits (C, D and their trailer variants) the common format is the same: 30 questions, 30 minutes, 3 errors max. What changes is the question bank, which adds blocks specific to goods or passenger transport, tachograph, driving and rest periods. But the test mechanics — number, time and allowed errors — are identical.
The only exception is the AM (moped) licence, designed for 15-to-17-year-old riders: the exam is 20 questions with 2 errors max in 20 minutes. The proportion holds (90 % accuracy required), but the test is shorter because the moped-specific syllabus is narrower than the B-licence one.
How to manage the 30 minutes during the exam
The most common trap isn't running out of time: it's the opposite. With time to spare, many candidates reread the prompts too often and induce their own doubts — they start switching correct answers to wrong ones. The practical rule: fast first pass (15–18 minutes), answer what you know for sure and flag the ones that block you. Second pass only on flagged questions, max 1 minute each. Third and final pass to double-check everything before submitting.
sacatelcarnet simulations show a visible timer — not as punishment, but to train your pace. After 5–10 timed simulations you should naturally finish in 18–22 minutes. If your simulation takes more than 28 minutes, you're still hesitating too much: you need more revision on the topics where you stop to think, not more tests.
How the 30 questions are spread across topics
The DGT does not publish an exact distribution — the bank is dynamic and each exam is randomly generated against internal quotas — but from analysis of real exams and released model tests, the approximate B-licence breakdown is: 6–8 signage questions (vertical and horizontal), 3–5 on priority and intersections, 3–4 on speed, 2–3 on alcohol/drugs/medical, 2–3 on mechanics and active safety, 2–3 on basic rules (registration, documents, fines), 2–3 on defensive driving and manoeuvres, 1–2 on insurance and liability, and 1–2 on cargo, trailers or private transport.
Practical implication: mastering signage and priority alone covers roughly 33–43 % of the exam. That's why those two blocks are the most cost-effective to review in the final week before the real exam.
Why people fail a 30-question test
The most common cause isn't lack of study: it's misreading the prompt. The DGT writes questions with decisive keywords — "always", "never", "except", "only", "at least" — and many candidates miss them. A prompt with "always" demands a categorical exception; one with "except in" admits the general rule minus one case. Switching answers because you doubt usually ruins a correct first instinct.
Second cause: studying only by topic and never doing full simulations. Knowing signage 100 % doesn't pass you if you've never trained the block-switching (sign → priority → mechanics → alcohol) under pressure. You need the random mix of a real simulation to get your head used to the topic-jumping.
Third cause: booking the real exam while still not consistently passing simulations. The objective "you're ready" signal: 5 consecutive simulations with 1 wrong or fewer. Below that, booking early only burns a sitting and triggers an extra fee.
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Frequently asked questions
- Why does the DGT exam have exactly 30 questions?
- The 30-question / 3-error / 30-minute format is fixed by the Spanish General Drivers' Regulation and by the DGT itself for the B licence and every permit that shares the common exam (A1, A2, A, B+E, C1, C, D1, D). It balances covering enough syllabus blocks (signage, priority, speed, alcohol, mechanics, defensive driving) with keeping the test within a manageable time window. The only category with a different format is AM, which has 20 questions, 2 errors max and 20 minutes.
- How many wrong answers are allowed on a 30-question test?
- A maximum of 3 wrong answers out of 30 to pass. At the fourth mistake the exam is failed, regardless of how many you got right. The real bar is 90 % accuracy: you need at least 27 correct answers.
- How long do I have to answer the 30 questions?
- 30 minutes in total — an average of 1 minute per question. In practice you don't need that much: most candidates finish in 15–20 minutes. The important thing is reserving the last 5 minutes for reviewing questions you flagged — order doesn't count and you can return to them before submitting.
- Is the 30-question test always for the same permit?
- Yes. The official exam is generated from the question bank that matches the permit you are sitting. For the B licence the 30 questions come from the B bank (common + car-specific). For C or D, the bank is the professional one with transport-specific blocks. On sacatelcarnet you pick the permit before launching the simulation and the bank filters automatically.
- How many 30-question simulations should I do before the real exam?
- The benchmark most correlated with first-time pass is at least 15 full 30-question simulations before the real exam. In your last 5 consecutive simulations you should be missing 1 or 2 questions at most — that's the signal you're ready to book the official sitting. Below that, keep practising.
- Are there picture questions on the 30-question test?
- Yes. The DGT exam includes image questions — sign photos, intersection diagrams, real traffic-situation photographs. Roughly half of the official bank carries visual support. The sacatelcarnet simulation replicates this format: picture questions appear with the photo or diagram, just like the real exam.
- Can I skip questions and come back to them?
- Yes. During the real exam you can answer in any order, skip questions and flag them for review. The screen shows a side panel with each question's status (answered, blank, flagged). Until you press "Submit" you can edit any answer. We recommend skipping the ones that block you, finishing the ones you know, and returning at the end with time and a cool head.