CLASSAX is a new concept for automatic vehicle detection, Automatic Vehicle Classification (AVC) and traffic data collection, combining the advantages of axle sensors with those of an inductive loop instead of considering both detection principles to be competing.
A CLASSAX system is capable of working with sensors, which can all be installed flush with the roadway surface to protect them from possible damage. The detection zone is very well defined and can be made very short, which enhances reliability with slow traffic and is an essential requirement for true multi-lane capability. Moreover, all the detection means required are available with static response, so the system is truly able to cope with traffic speeds down to zero.
Along with the philosopy of detection CLASSAX also includes a new method for setting up classification schemes. Traditional AVC systems have fixed behaviour which is difficult, or even impossible, to modify because they were designed from scratch for distinction of a pre-defined set of vehicle classes. In addition, in order for the characteristics of a particular class to be recognised, the system requires a large collection of vehicle data. To compound this problem, this vehicle data, as well as the registration of the vehicle’s according parameters, must be very accurate. This adds considerable extra effort to the development so setting up custom AVC systems is very expensive.
With CLASSAX, vehicle class characteristics are determined by a teach-in process utilizing real traffic; no initial inquiry of vehicle data is necessary. All parameters are measured the same way as in operation, thus any systematic errors are automatically taken into account and therefore cease to be errors. The customer can define any set of vehicle classes desired: if they are only indicated by different vehicle characteristics the system will identify them faithfully. The effort added to the system price by this teach-in process is negligible compared to what setting up a traditional custom AVC system requires.
Originally intended to be just an AVC system especially suitable for extremely slow moving traffic, CLASSAX can bring about much more than this. Being an example of a whole that is more than the sum of its parts, it constitutes an instrument of outstanding versatility. Possible applications include vehicle detection, classification and counting, axle counting, traffic statistics, traffic monitoring and control, vehicle recognition and weigh-in-motion.