That part may need to be done manually or with a elevation labelstyle, either way it will not do it automitcally unless it's a band style. Try playing around with the band styles and you may find something that works for you. If you always had a grade break, which almost never happens with a complex roadway, then you could just setup a grade break labelstyle.
R10 - 2020 ACAD
2008 - 2020 Civil 3D
2014 - 2020 Plant 3D
2014 - 2020 Revit
V8i - V8i SS4 Microstation
Infraworks
2018-2020 Inventor
2020 Navisworks