Index: /trunk/src/org/openstreetmap/josm/tools/RightAndLefthandTraffic.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/tools/RightAndLefthandTraffic.java	(revision 14031)
+++ /trunk/src/org/openstreetmap/josm/tools/RightAndLefthandTraffic.java	(revision 14032)
@@ -38,4 +38,5 @@
 /**
  * Look up, if there is right- or left-hand traffic at a certain place.
+ * See <a href="https://en.wikipedia.org/wiki/Left-_and_right-hand_traffic">Left- and right-hand traffic</a>
  */
 public final class RightAndLefthandTraffic {
@@ -58,5 +59,6 @@
      */
     public static synchronized boolean isRightHandTraffic(LatLon ll) {
-        return !rlCache.get(ll);
+        Boolean value = rlCache.get(ll);
+        return value == null || !value;
     }