themselves next to a road in order to detect a few offenders, with a clear-up rate of 100%, the latter always being identified. The proportion of placements in police custody that continue for more than twenty four hours28 as well as the length of police custody as a whole are relatively uniform. Excluding the case of Montereau, the highest level is twice that of the lowest (ranging from 11% to 22%) and divergence from the average is small. The average length of custody, which is relatively high, especially when compared to the length of questioning, varies between a minimum of 12 hours 36 minutes and a maximum of 20 hours 38 minutes. In this case again, methods of operation are as important as criminal activity itself in accounting for these differences. Finally, the number of placements in police custody per day reflects considerable differences in the activity of police stations, which are obviously dependent on data concerning the population of the police district29, the volume of crime and the activity of the departments. The highest level (11.2 per day at Metz) is ten times greater than the lowest (1.2 at Niort), which naturally leads to very different workloads from one establishment to another, as well as different workflow management. The workload of one police station may be temporarily increased, because persons placed in police custody in other establishments are sent to it due lack of personnel, above all at night. Within the sharp contrasts of this overall picture, the conditions of exercise of fundamental rights now need to be examined. 2.2.1.2 Data concerning Practical Details of Police Custody For the purposes of clarity, the data is once again divided into two tables. They list about fifteen items which the inspectors are careful to verify during each of their inspections. Once again, the table is far from reflecting the reality of inspections30, but nevertheless gives an initial idea of the practical details of police custody. Amiens Angers Chartre Chessy Douai Metz s Montereau Niort No. of individual cells 4 5 3 4 7 2 6 0 No. of collective cells 1 1 1 1 0 2 1 2 No. of cells for minors 0 0 1 0 1 2 0 0 5 6 5 5 8 6 7 2 Total cells 28 National average: 17.3% en 2009 (excluding road traffic offences; though the latter seldom lead to extensions of police custody); 18.2% in 2010. 29 The average population of the seventeen police districts studied comes to 94,900 inhabitants, for a range of between 31,943 (for Chessy) and 204,500 (for Douai). 30 For an exhaustive view refer to the inspection reports of police custody facilities published in their entirety on the cglpl.fr website. 33