We have been mapping turn lanes in many cities in the United States to improve navigation data present in OpenStreetMap. Adding turn lanes requires splitting existing roads at the exact point where a lane begins, and adding appropriate tags. To help the team with this task, we have developed the Knife tool, a plugin for the Java OpenStreetMap Editor (JOSM), that will split ways with a single click.
The Knife tool is much faster compared to using the default split action in JOSM. The Knife tool intelligently determines which way to split at intersections, and automatically selects the way that may get turn lane tags.
Using the Knife tool
First, download the Java archive file and copy it to your JOSM plugin folder. Next, activate the plugin from JOSM Preferences > Plugins > auto_tools and then restart JOSM. Now you can use the shortcut T to split ways by a single click.
The Knife tool at work
At Mapbox, we are constantly trying to improve OpenStreetMap tools to make mapping easier and faster. Give the Knife tool a spin and let me or Ruben know if you have any questions.