diff --git a/data/core.yaml b/data/core.yaml
index 7af8cba01..3d26200e9 100644
--- a/data/core.yaml
+++ b/data/core.yaml
@@ -425,7 +425,7 @@ en:
     tooltip: "Street-level photos from Mapillary"
     title: "Photo Overlay (Mapillary)"
   mapillary_signs:
-    tooltip: "Traffic signs from Mapillary"
+    tooltip: "Traffic signs from Mapillary (must enable Photo Overlay)"
     title: "Traffic Sign Overlay (Mapillary)"
   mapillary:
     view_on_mapillary: "View this image on Mapillary"
diff --git a/dist/locales/en.json b/dist/locales/en.json
index d263ffd20..c05233a8f 100644
--- a/dist/locales/en.json
+++ b/dist/locales/en.json
@@ -512,7 +512,7 @@
         "title": "Photo Overlay (Mapillary)"
     },
     "mapillary_signs": {
-        "tooltip": "Traffic signs from Mapillary",
+        "tooltip": "Traffic signs from Mapillary (must enable Photo Overlay)",
         "title": "Traffic Sign Overlay (Mapillary)"
     },
     "mapillary": {
diff --git a/js/id/ui/map_data.js b/js/id/ui/map_data.js
index 3b59b361f..70b001eed 100644
--- a/js/id/ui/map_data.js
+++ b/js/id/ui/map_data.js
@@ -39,20 +39,35 @@ iD.ui.MapData = function(context) {
             update();
         }
 
-        function toggleLayer(which) {
+        function showsLayer(which) {
             var layer = layers.layer(which);
             if (layer) {
-                layer.enabled(!layer.enabled());
+                return layer.enabled();
+            }
+            return false;
+        }
+
+        function setLayer(which, enabled) {
+            var layer = layers.layer(which);
+            if (layer) {
+                layer.enabled(enabled);
                 update();
             }
         }
 
+        function toggleLayer(which) {
+            setLayer(which, !showsLayer(which));
+        }
+
         function clickGpx() {
             toggleLayer('gpx');
         }
 
         function clickMapillaryImages() {
             toggleLayer('mapillary-images');
+            if (!showsLayer('mapillary-images')) {
+                setLayer('mapillary-signs', false);
+            }
         }
 
         function clickMapillarySigns() {
@@ -128,8 +143,13 @@ iD.ui.MapData = function(context) {
             mapillarySignLayerItem
                 .classed('active', showsMapillarySigns)
                 .selectAll('input')
+                .property('disabled', !showsMapillaryImages)
                 .property('checked', showsMapillarySigns);
 
+            mapillarySignLayerItem
+                .selectAll('label')
+                .classed('deemphasize', !showsMapillaryImages);
+
             // Exit
             mapillaryImageLayerItem.exit()
                 .remove();
@@ -200,6 +220,10 @@ iD.ui.MapData = function(context) {
                 .property('disabled', !hasGpx)
                 .property('checked', showsGpx);
 
+            gpxLayerItem
+                .selectAll('label')
+                .classed('deemphasize', !hasGpx);
+
             // Exit
             gpxLayerItem.exit()
                 .remove();