What evidence is there that intensive driving lessons work?

What evidence is there that intensive driving lessons work?
I do not have figures for the driving test pass rate following intensive lessons. However the following may be of interest:The overall pass rate in the UK is 42%. This suggests that the majority of people taking the test are not sufficiently prepared. Also the DSA (Driving Standards Agency) states that, on average, people who pass the test have had around 40 hours of professional tuition plus private practice with family or friends.It should also be borne in mind that, having passed the test, a driver is free to drive unaccompanied, or with a car full of friends, on all kinds of roads including motorways. It is difficult to see how sufficient experience to cope with this can be gained in a short burst of intensive lessons.Remember that an examiner has only 40 minutes to assess a candidate's driving ability. Passing the test should not be an end in itself. Consider the very high percentage of casualities in the age range 17 to 21.