How can I pinpoint tight corners on a road dataset that might cause longer/larger vehicles difficulty in driving around.


  • Ignore turns into junctions. Just interested in corners along a single road.
  • Road network is a polyline layer. No arcs involved.
  • Road width is an attribute.
  • A large vehicle can be defined as a semi-truck.

Ideal Solution:

The end goal would be for a map showing potential areas on a road network that would be best avoided by larger vehicles. Ideally this would have a score value as opposed to a yes/no value, to signify how tricky the particular corner is, depending on the size of vehicle.

I have likely not provided enough information, so feel free to ask more Qs via comments and ill supplement my Q with more info. For info, this was a question I was posed, and I had some ideas, but would love to hear what your thoughts are on a potential workflow to solve this question using ArcGIS Desktop.


This is known as swept-path analysis. It is one of those calculations that seems initially to be relatively trivial but soon becomes obvious that there is a lot more to it because it is not just the tightness of the turn that is important.

Some of the other things to consider include:

  • Length of the vehicle and point of articulation.
  • Turning circle of the cab, vs. the trailer.
  • Does your vehicle have rear-wheel steering?
  • May the vehicle use the full width of the road?

The problem becomes more complex in 3D where you may be able to accept oversail of the trailer across the road edge but have to account for grounding when turning a corner and going up-hill (this scenario assumes rear-wheel steering).

There is some specialist proprietary software solutions out there including a plug-in for AutoCAD. There is a good looking package called 'Auto Turn' available as a plugin for Bentley.

I have developed my own solution which uses OGR and Blender. The map shows pinch points and locations of likely oversail. I use this to provide a commercial service (especially for the Wind Farm industry) so forgive me for not sharing it here. However a search for "swept path analysis" will help you.

  • this is an awesome answer, and given me the right words for doing more research. However, still looking for an answer that actually attempts to provide a workflow into solving the issue, ideally with tools within ArcGIS
    – jakc
    Mar 7 '13 at 12:42
  • Does your plugin do vertical and horizontal curve analysis as well?
    – dassouki
    Mar 7 '13 at 13:13
  • It is currently only 2D. I could write a component to do 3D I guess, but so far that hasn't been requested so I focus on other things. It is more of a user-directed script rather then a neatly packed plugin as I am the only user (therefore I don't need any nice UI). Mar 7 '13 at 13:29

Not sure for ArcGIS. CAD software like AutoCAD (but also cheaper solutions like BricsCAD or ZWCAD) are usually compatible with swept path solutions. Could be an online solution too, maybe check out this swept path analysis site

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.