I'm looking for an Open Source GIS application that supports Linear Referencing and Dynamic Segmentation for the development of a road inventory system. I already know about GRASS but I'd like to know if there are any other options.
The other option that I have found is using PostGIS. This software provides the spatial extensions for the PostgreSQL rdbms. These are both Open Source. There is a Linear Referencing Component described here: Link.
You may load the plugin for QGIS through the Plugin Menu. Use the Fetch Python Plugins command, then filter the search like the screenshot below:
Where the button currently shows "Reinstall", you will have the option to simply "Install" the plugin.
These are all open source products, and have active development, so I would say they are definitely worth checking out.
You have another one: LRS (to use in QGis 2.0 or upper). All the documentation of the plugin can be consulted here: http://blazek.github.io/lrs/release/help.0.3.0/index.html.