Roadside Severity - Distance - Sloping Ground

When determining the distance to a road side object, should the distance be weighted depending on the slope of the ground between the travel lane and the object. Austroads has information regarding clear zones that would appear appropriate to use here, for instance a distance of 8.5m on flat ground is equivalent to 10.0m on a slope of 6:1 and 13.5m on a slope of 4:1. Also current research suggests discounting slopes steeper than 4:1.

This is a good question Paul, thanks. For simplicity and consistency, we don’t attempt to weight the distance depending on the slope. A simple horizontal distance should be measured.