# Radius of curvature for curves in road segments for entire road network

I have a road network shapefile for a US state and I am trying to derive the radius of curvature for road segments in this shapefile. I need to be able to perform this task within just a few functions for thousands of road segments.

The road segments vary between 0.2 miles and maybe 5 or so miles. Each segment has several curves, but I am only interested in curves small enough to force a vehicle to make a reasonable turn. This should reduce the number of curves of interest per segment to a max of 1 or 2, with many segments not having such curves at all. I have not determined the maximum radius of the curve (the threshold) I would like to use.

For segments with only 1 such curve, I would like to obtain the values of those curves for those segments, and for those with more than 1, an average will do.

• A helpful link forums.arcgis.com/threads/… – Alex Tereshenkov Jun 11 '14 at 18:04
• Would calculating sinuosity of each road segment be helpful to you? There are ready-to-use tools for this I could share. – Alex Tereshenkov Jun 11 '14 at 18:11
• Because a segment (which is a portion of a straight line, by definition) has infinite radius of curvature, surely your intent is to estimate a mean radius of curvature throughout series of connected segments. The estimates can vary depending on how long a portion of the road is used as well as the estimation procedure. The output in principle is a continuously varying function of location, so there's also an issue of how that should be represented. Choosing a good solution depends on understanding why you need this calculation. Could you edit the question to provide that kind of context? – whuber Jun 11 '14 at 21:17
• Incidentally, one solution, with working code, is posted at gis.stackexchange.com/a/37078/664--but it's not clear whether that's what you're looking for. – whuber Jun 11 '14 at 21:18
• whuber- i will add more detail to the question. – VT2 Jul 16 '14 at 12:34