ABSTRACT
The total number of cases analysed was 653, distributed among the eight divisions of the Police District as shown in Table 27 . It is stressed that this is the total number of cases that came within the terms of reference of this research, and it will not cross-check with the statistics for prosecutions shown in the Home Office Returns of Offences relating to Motor Vehicles, or with the returns of convictions made by the police. This is because:
It was necessary to rely on busy police clerks to find the cases in three divisional offices, and it may be that some were missed.
The chronological basis for inclusion or exclusion was the date of conviction. Hence, offences that occurred within the period 1957–59 were not included unless the offenders were convicted within the period also.
Offenders were counted only once in the category of the principal offence; e.g. an offender convicted for driving under the influence and for dangerous driving also, was counted once only: in this case under the former offence. (Where, as in this example, the offences were of nomin-ally equal seriousness, the choice of one or other as the principal offence was made arbitrarily, according to the hierarchy in which the six offences are shown in Table 27 .)
Certain convicted offenders were excluded to avoid overloading the research (as explained onp. 56 above): In cases of failing to stop, and failing to insure, aiders and abettors were excluded, and so were all those who lived outside the District; and, to reduce the amount of data, a random sample was taken of one in ten of the persons within the District convicted for failing to insure. Moreover, insurance offences were not included where they were the ‘automatic’ consequence of another offence that was not within the scope of the research, e.g. taking and driving away a vehicle without the owner's consent.
