Time-Space diagram
Time-space diagram of synchronised traffic signals drawn by the new YKGraph


What is YKGraph

YKGraph (in Finnish YKaavio) is freeware for drawing and planning time-space diagrams of coordinated (synchronised) traffic signals.

What is a time-space diagram

Time-space diagram is the way of showing the settings of the coordinated traffic signals along the main street.

In US the coordination schema is often called a Green band. In Europe, especially in Germany, it is usually known as a Green wave.

What is YKGraph intended

YKGraph is for planning and drawing tool for the time-space diagram of coordinated traffic signals.

Time-space diagram drawn by YKGraph gives a clear view of the green wave (green band) in both directions. It also indicates the junctions, where the vehicles driving along the green wave must slow down or even stop.

YKGraph is based on the well-known graphical method presented first time in the Finnish National Traffic Signal Planning Handbook LIVASU-1978.

The latest version of YKGraph includes option to consider the suitability of the green wave for public transport and bicycles in a separate lane.

New YKGraph 3 is published

Start the latest version 3.01 of YKGraph here

The new YKGraph 3 is based on JavaScript. It works with Chrome and Opera browsers. Other browsers have serious problems, especially with file operations and using menu.

More information is available in the Quick help of YKGraph.

The current version 3.0 includes some shortcomings:
- Random variation of tram stop times is missing.
- Public transport has an own lane. Other traffic on that lane is not considered
- Opposite direction of trams and bicycles is missing - coming to the final versions
- Movement label numbers are fixed (from 0 to 12) and intergreens are specified only for junctions, not between conflicting movements.
- Intergreens between conflicting movements are fixed in each junction.
- YKGraph is not fast enough for large data processing - short routes, eg. 5 to 10 junctions are OK.

Some information of the progress of YKGraph you will find here.