Index: /trunk/src/org/openstreetmap/josm/data/validation/OsmValidator.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/data/validation/OsmValidator.java	(revision 5901)
+++ /trunk/src/org/openstreetmap/josm/data/validation/OsmValidator.java	(revision 5902)
@@ -33,4 +33,5 @@
 import org.openstreetmap.josm.data.validation.tests.DuplicateWay;
 import org.openstreetmap.josm.data.validation.tests.DuplicatedWayNodes;
+import org.openstreetmap.josm.data.validation.tests.Highways;
 import org.openstreetmap.josm.data.validation.tests.MultipolygonTest;
 import org.openstreetmap.josm.data.validation.tests.NameMismatch;
@@ -110,6 +111,10 @@
         PowerLines.class, // ID 2501 .. 2599
         Addresses.class, // ID 2601 .. 2699
+        Highways.class, // ID 2701 .. 2799
     };
 
+    /**
+     * Constructs a new {@code OsmValidator}.
+     */
     public OsmValidator() {
         checkValidatorDir();
Index: /trunk/src/org/openstreetmap/josm/data/validation/tests/Highways.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/data/validation/tests/Highways.java	(revision 5902)
+++ /trunk/src/org/openstreetmap/josm/data/validation/tests/Highways.java	(revision 5902)
@@ -0,0 +1,106 @@
+// License: GPL. See LICENSE file for details.
+package org.openstreetmap.josm.data.validation.tests;
+
+import static org.openstreetmap.josm.tools.I18n.tr;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+
+import org.openstreetmap.josm.command.ChangePropertyCommand;
+import org.openstreetmap.josm.command.Command;
+import org.openstreetmap.josm.data.osm.Node;
+import org.openstreetmap.josm.data.osm.OsmUtils;
+import org.openstreetmap.josm.data.osm.Way;
+import org.openstreetmap.josm.data.validation.Severity;
+import org.openstreetmap.josm.data.validation.Test;
+import org.openstreetmap.josm.data.validation.TestError;
+import org.openstreetmap.josm.tools.Utils;
+
+/**
+ * Test that performs semantic checks on highways.
+ * @since 5902
+ */
+public class Highways extends Test {
+
+    protected static final int WRONG_ROUNDABOUT_HIGHWAY = 2701;
+    
+    protected static final List<String> CLASSIFIED_HIGHWAYS = Arrays.asList(
+            "motorway", "trunk", "primary", "secondary", "tertiary", "living_street", "residential", "unclassified");
+
+    /**
+     * Constructs a new {@code Highways} test.
+     */
+    public Highways() {
+        super(tr("Highways"), tr("Performs semantic checks on highways."));
+    }
+    
+    protected class WrongRoundaboutHighway extends TestError {
+
+        public final String correctValue;
+        
+        public WrongRoundaboutHighway(Way w, String key) {
+            super(Highways.this, Severity.WARNING, 
+                    tr("Incorrect roundabout (highway: {0} instead of {1})", w.get("highway"), key), 
+                    WRONG_ROUNDABOUT_HIGHWAY, w);
+            this.correctValue = key;
+        }
+    }
+    
+    @Override
+    public void visit(Way w) {
+        if (w.isUsable()) {
+            if (w.hasKey("highway") && w.hasKey("junction") && w.get("junction").equals("roundabout")) {
+                Map<String, List<Way>> map = new HashMap<String, List<Way>>();
+                // Count all highways (per type) connected to this roundabout
+                // As roundabouts are closed ways, take care of not processing the first/last node twice
+                for (Node n : new HashSet<Node>(w.getNodes())) {
+                    for (Way h : Utils.filteredCollection(n.getReferrers(), Way.class)) {
+                        if (h != w && h.hasKey("highway")) {
+                            List<Way> list = map.get(h.get("highway"));
+                            if (list == null) {
+                                map.put(h.get("highway"), list = new ArrayList<Way>());
+                            }
+                            list.add(h);
+                        }
+                    }
+                }
+                // The roundabout should carry the highway tag of its two biggest highways
+                for (String s : CLASSIFIED_HIGHWAYS) {
+                    List<Way> list = map.get(s);
+                    if (list != null && list.size() >= 2) {
+                        // Except when a single road is connected, but with two oneway segments
+                        Boolean oneway1 = OsmUtils.getOsmBoolean(list.get(0).get("oneway"));
+                        Boolean oneway2 = OsmUtils.getOsmBoolean(list.get(1).get("oneway"));
+                        if (list.size() > 2 || oneway1 == null || oneway2 == null || !oneway1 || !oneway2) {
+                            // Error when the highway tags do not match
+                            if (!w.get("highway").equals(s)) {
+                                errors.add(new TestError(this, Severity.WARNING, 
+                                        tr("Incorrect roundabout (highway: {0} instead of {1})", w.get("highway"), s), 
+                                        WRONG_ROUNDABOUT_HIGHWAY, w));
+                            }
+                            break;
+                        }
+                    }
+                }
+            }
+        }
+    }
+    
+    @Override
+    public boolean isFixable(TestError testError) {
+        return testError instanceof WrongRoundaboutHighway;
+    }
+
+    @Override
+    public Command fixError(TestError testError) {
+        if (testError instanceof WrongRoundaboutHighway) {
+            return new ChangePropertyCommand(testError.getPrimitives().iterator().next(), 
+                    "highway", ((WrongRoundaboutHighway) testError).correctValue);
+        }
+        return null;
+    }
+}