Identifying Dangerous Curves

[DorotheaKnigge]

Hello,       

We would like to identify dangerous tight curves in our road database.

To start I calculated a field called 'Sinuosity' with the following expression:

"!Shape.Length! / (math.sqrt(math.pow((float( !Shape.FirstPoint.X!) - float( !Shape.LastPoint.X!)), 2) + math.pow((float( !Shape.FirstPoint.Y!) - float( !Shape.LastPoint.Y!)), 2)))"

I then downloaded a geoprocessing script called 'Identify True Curves' which creates two output feature classes:

OutputCurvePoints and OutputWithCurves

It also creates two temp files: tmpSourceVertices and tmpDensifiedVertices

I have successfully run the model but it is really not what I am looking to accomplish.

Does anyone have a way to find these dangerous hairpin turns?

I am using ArcInfo 10.1.

Thank you,

Dorothea

[Anonymous User]

GitHub - KDOTGIS/HorizontalCurve: KDOT commissioned URS to create this horizontal curve calculator w... 

Here is a horizontal curve tool that was created for Kansas DOT.  The tool looks at road centerline geometry and calculates curve radius assuming circular curves, and also gives a R-squared indicator that can help to identify poorly digitized curves, spiral curves, or compound curves. 

"Dangerous curves" is a somewhat subjective adjective, I suppose you are looking for a relationship between curve radius, speed limit, and then adding in weighting factors including traffic volumes, crashes located near the curve, and then hopefully contributing circumstances to those crashes.  Dangerous curves also might have issues with signage, elevation, sight obstructions, any other number of systemic safety attributes.