Abstract: A system for the geolocation of vehicles traveling on a guideway comprises the vehicles and markers distributed episodically along the guideway. The vehicles are equipped with a sensor for detecting a physical characteristic of the markers, and a computer for supplying location information as a function of signals delivered by the sensor. The computer stores a database comprising a recording of the distribution of the markers on the guideway. The markers having a physical characteristic detectable by the sensors. The markers each belong to one and only one class among a plurality of classes of physical objects, and the physical characteristic of all the markers of a class have the same property during detection by one of the sensors. The markers are randomly distributed on the guideway, with an ordered recording of the class to which each of the markers arranged on the guideway is stored in the database.

Abstract: A modular block and a retaining wall filled of the modular blocks, each modular block having a body portion with first and second opposed ends, an interior hollow portion to receive a ballast, the first one of the opposed ends having a plurality of tenons extending outwardly therefrom, a second one of the opposed ends having a plurality of mortices formed therein, the arrangement being such that the modular block be connected to an adjacent modular block at varying angles by means of the mortices and tenons. The retaining wall may conveniently be used as a flood containment structure.