READING - Speed Enforcement by Section Control
Section control is a method of speed enforcement involving a series of cameras installed over a stretch of road. An image and data are recorded for each vehicle as they enter and leave two points in the system (a section of road). The data are then used to calculate the average speed of the vehicle by dividing the time taken to travel through two points by the distance between them. The basis for introducing section control is that it encourages drivers to reduce their speed across an entire section of road and greater levels of behaviour changes can therefore be obtained. There are indeed multiple cases documenting speed reductions across entire sections of roads, consequently having a positive impact on the number of collisions and casualties. The two paragraphs above are quoted from the document below, which also points out that this system results in other benefits in addition to speed control. In one section a 5 to 10% reduction in air pollution was noted.