Left- and right-hand traffic

JOSM has an internal database of areas with left-hand traffic. This was added in r7193. This is used in some Styles for correct display. Examples are the default internal mappaint style (for cycleway lanes and tracks on highways) or Styles/Maxspeed (for maxspeed:forward and maxspeed:backward).

You can download the data ​here (click on raw format on the bottom of the page) and load the file in JOSM to investigate the borders. The areas in the file describe the areas with left-hand traffic. All other areas use right-hand traffic.

You can use the pseudo classes :righthandtraffic for right-hand traffic and !:righthandtraffic for left-hand traffic in your mapcss stylesheet. See Help/Styles/MapCSSImplementation for more information.

Screenshot of the areas with left-hand traffic: