1. A method of constructing a digital model of a road, which comprises: acquiring a first set of data relating to the geometry of the road by means of a differential global positioning system (DGPS), acquiring a second set of data relating to the geometry of the road by means of a hybridised inertial unit with a global positioning system (GPS), indexing the values of the said first and second steps of data by determining their confidence level, eliminating the values of the said first and second sets of data below a predefined confidence threshold in order to obtain a first set and second set of corrected data, aggregating the data of said first and second set of corrected data, aggregating the data of said first and second sets of corrected data in order to obtain the digital model of the road.