HERE Road Roughness

HERE Road Roughness - FAQ

#1 What does RoughnessCategoryFrom vs. …To mean?

This is for bidirectional links with traffic that goes both directions. The reference node is always the southernmost node. In the case where both ends of the link are at the same height the western node is the reference node. For this example, the side of the road going south-east towards the reference node of the link is all rated at 3. The side going towards the non-reference node of the link headed north-west are all rated at 2. These calculations are from different drives going different directions and that is why they have different values at the same location.

#2 What does mean category “0” ?

'0' is a perfect road.

#3 Do the “RoughnessCategoryValues” base on the IRI values and if Yes, what are the IRI-borders to next Roughness-class?

Yes, 0-3 = Good, 3-7 = Fair, 7+ = Poor. See chart below.

#4 What is the resolution of the IRI values? So how many values per meter on the road?

It might be around 6 meters for most drives.

#5 Who is doing such IRI measurements on German roads?

It’s calculated from HERE True drive data.

#6 How often are the IRI and Roughness values updated? Once per Year?

The product is created quarterly and uses the newest HERE True drive for each road segment.

#7 Do you have any more detailed documentation concerning map-matching information as IRI/Roughness etc. beside “here_layer_attribute”?

Pl. see image below.