You find the relevant section of code [here][1]. The default color is HSB((v / 45 * 45 / 300), 1, 1) where *v* is the speed in m/s. [1]: https://josm.openstreetmap.de/browser/josm/trunk/src/org/openstreetmap/josm/gui/layer/GpxLayer.java

You find the relevant section of code [here][1]. The default color is HSB(v*45/300, HSB((v * 45 / 300), 1, 1) where *v* is the speed in m/s. [1]: https://josm.openstreetmap.de/browser/josm/trunk/src/org/openstreetmap/josm/gui/layer/GpxLayer.java

You find the relevant section of code [here][1]. The default color is HSB(v/45/300, HSB(v*45/300, 1, 1) where *v* is the speed in m/s. [1]: https://josm.openstreetmap.de/browser/josm/trunk/src/org/openstreetmap/josm/gui/layer/GpxLayer.java

You find the relevant section of code [here][1]. The default color is HSB(v/45/300, 1, 1) where *v* is the speed in m/s. [1]: https://josm.openstreetmap.de/browser/josm/trunk/src/org/openstreetmap/josm/gui/layer/GpxLayer.java