Integraal verkeerstoezicht op alcoholgebruik, snelheid, autogordels en bromfietshelmen : verslag van een experiment, uitgevoerd door de politie in de subregio Leiden.

In 1990, the national and local police carried out an experimental integral traffic enforcement policy in the subregion of Leyden (situated in the western part of the Netherlands). The purpose of the experiment (See also IRRD 855462 and 855463) was to combine the enforcement on different important traffic offences as much as possible in order to increase efficiency. The experimental enforcement was concerned with: drinking and driving of road users, speeding, the use of seat belts, and the use of helmets by moped riders. Besides police enforcement, the experiment also consisted of publicity. The behavioural measurements consisted of a before and after study. About 5 months after the start, 486 drivers who regularly travelled in the subregion of Leyden were surveyed by telephone. The main results of the investigation are as follows: (1) 6863 Offenders in exceeding the speed limits were fined; (2) A deterioration of the speed behaviour on 80 km/h roads was found; (3) The average speed on 50 km/h roads decreased from 54 km/h to 53 km/h; (4) A slightly, non-significant increase in the number of the drivers with an punishable blood alcohol content (equal to or more than 0.5 per cent) exclusively demonstrated in relatively slight offences (BAC between 0.5 and 0.8 per cent); (5) The number of heavier offenders (BAC equal to or more than 0.8 per cent) remained practically the same; (6) The number of drivers using alcohol, but without exceeding the legal BAC limits (between 0.2 and 0.5 per cent) decreased from 10.1% to 8.4%; (7) As regards the enforcement on seat belt use, nearly 7000 drivers were stopped of whom 277 drivers were fined for not wearing the belt; (8) In the period between the before measurement in December 1989 and the after measurement in January 1991, the belt use on the front seat of cars increased from 57% to 62%. This development favourably appeared to deviate from the national trend. However the goal, namely to increase the use of belts on the front seat of cars to 90%, was not achieved; (9) A few observations done at the measurements of belt use generally appeared to correspond with the results of the national investigation; and (10) despite a slight improvement in the use of moped helmets, especially regarding fastening the chin strap, the level of use was alarmingly low.