The practical driving test is taken on the road, with a professionally trained DSA examiner directing the candidate around a pre-determined route. The examiner marks the candidate for driving faults, serious faults, and dangerous faults. A candidate will fail the test if he or she accumulates any serious or dangerous faults, or more than fifteen driving faults. If a candidate accumulates several driving faults in the same category, the examiner may consider the fault habitual and mark a serious fault in that category. The test usually lasts 38 to 40 minutes in a standard test, or approximately 70 minutes when the candidate is taking an extended test after having had their licence revoked.