Sometimes two designers design their own part of the road, which they then want to combine into a single one. In the Plateia software, you have several options for combining two or more parts of the road into one. The video below shows the best way in which the program correctly recognizes all horizontal axis elements, including spirals. These otherwise present a problem when we want to directly convert a polyline into an axis.
NOTE! In the video, it is shown that the second part of the road starts at station, which is the same as the station at the end of the first part. This is the correct design approach. But even if the second part of the axis started at station 0, and the rest was the same as in the video, the program would correctly combine the parts into a common axis.