diff --git a/css/map.css b/css/map.css
index dc970f310..4626ed13f 100644
--- a/css/map.css
+++ b/css/map.css
@@ -629,6 +629,14 @@ path.casing.tag-bridge-yes {
     stroke: #333;
 }
 
+path.stroke.tag-highway.tag-tunnel-yes {
+    stroke-opacity: 0.3;
+}
+
+path.casing.tag-highway.tag-tunnel-yes {
+    stroke-opacity: 0.5;
+}
+
 path.stroke.tag-highway-construction,
 path.casing.tag-highway-construction {
     stroke-linecap: butt;
diff --git a/js/id/svg/tag_classes.js b/js/id/svg/tag_classes.js
index 5fd455e87..94f9034ee 100644
--- a/js/id/svg/tag_classes.js
+++ b/js/id/svg/tag_classes.js
@@ -2,7 +2,7 @@ iD.svg.TagClasses = function() {
     var keys = d3.set([
         'highway', 'railway', 'waterway', 'power', 'motorway', 'amenity',
         'natural', 'landuse', 'building', 'oneway', 'bridge', 'boundary',
-        'leisure', 'construction', 'place'
+        'tunnel', 'leisure', 'construction', 'place'
     ]), tagClassRe = /^tag-/,
         tags = function(entity) { return entity.tags; };