A coupled alignment is supported on an alignment already calculated to determine its position. At the final or initial point of the already calculated alignment, and with the corresponding azimuth, the layout elements of the coupled alignment concatenate.
It is defined by its radius, its length and the parameters of the input and output clothoids. Furthermore, it has a final item of data pertaining to the length (or an increase in length) of the alignment on which it is supported. In view of this latter data, and bearing in mind whether the alignment calculated is the previous or subsequent one, four subtypes can be distinguished between
TcpMDT