Step 2 - The first overpass

We will still use the basic road type because this type is easier when you need to measure.Now can we start with the first overpass. First we build a road from ground level, 12 unit long to a height of 9 meters.The next step is extend the road by 7 untis until it reaches the middle of the highway.And then we will extend the road to the other end. An important distance is the 5 unit length beween the highway and the parallel road. This 5 units we need for calculation of how long we need to extend the overpass. The length of the extention is based on the radius of the circle we are going to build. The length of the extention and the radius need to be the same.Since we extend the road by 7 units, see picture below, we have already done 2 units of the extention. That is marked with the red line.We are going to create circles with a radius of 6 units. Therefore we need to extend our road by 6 units from the parallel road. Since we have already done 2 units (7 units minus 5 units), we extend our road by another 4 units to make it 6 units. This 6 unit length is marked with a red line below.Now we going to draw the first part of the circle. We create a semi circular road of 6 units by 6 units, and with an angle of 90 degrees. At the same time we lower the height to 6 meters. The height is marked in green.We do this a second time, again with 90 degrees, 6 units by 6 units and now lowering the height to 3 meters.Now we need to remove parts of the parallel road.Do not remove them all, make sure you have some road left at both ends. If you have problems removing only a part of the road, you can create a small extra road and remove the roads from here.Now we can create the last part of the circle. Again 6 units by 6 units, 90 degrees and lowering the height with another 3 units to ground level.And then we extend the overpass to the parallel road.We have now created our first overpass. One lastthing to do is convert all roads of the overpass to highway ramp type of roads, because otherwise the second overpass will not fit next to this overpass.