Follow the steps to create a ditch in the median of a highway
1 - Set the edit mode
2 - First click in you in your road, and click witch mouse right button and select Insert Components
3 - Select the Battered Curb
4 - Click in the center of road, and Align to Start and the End of Road.
5 - Select the componente and click with mouse right button and select the option Flip Component.
6 - Repeat the step 3 and 4 but now insert the Stoped Grass Median
7 - Edit the Width and the Slope values
8 - Now insert the component called Shoulder
9 - Edit the component values width (0,50) and Slope (-100,0%)
10 - Insert again the Shoulder component, and edit the values Width (1,0) and Slope (0,0%)
11 - Repeat the steps to insert component shoulder, sloped grass median and finally the battered curb to the righ side of the ditch.
That´s it
Here the screencast showing the whole process.