profile grade break instead of vertical curve

[kailiwalker]

Do anyone know where to find guidance on roadway profile grade breaks. It seems everyone i talk to has a different answer. I have a roadway with a design speed of 35 mph with a 100' sag curve. i want to get rid of the sag curve and replace it with a grade break but not sure if an AD value of 1.5% is Ok

 

[CarlB]

The number I've heard is 1% maximum on a grade break.
Why not use a shorter curve length, say 20' to 40'.


Some discussion at thread194-174877

 

[civilman72]

Generally, a maximum vertical grade break without vertical curve is limited to the 0.5%-1.0% range. For instance, for a rural gravel road 1% may be allowable, but for a paved highway the limit is probably 0.5%. The design speed and surface material are the two main factors that are considered in these requirements.

 

[bank]

If it's a public road you should check local regulations. In these parts a vertical curve is required on public roads if the algebraic difference is 1% or more.