diff --git a/layers/transportation/update_route_member.sql b/layers/transportation/update_route_member.sql
index fd128139..83361abc 100644
--- a/layers/transportation/update_route_member.sql
+++ b/layers/transportation/update_route_member.sql
@@ -149,6 +149,17 @@ CREATE INDEX IF NOT EXISTS osm_route_member_ref_idx ON osm_route_member ("ref");
CREATE INDEX IF NOT EXISTS osm_route_member_network_type_idx ON osm_route_member ("network_type");
+/**
+* Discard duplicate routes
+*/
+DELETE FROM osm_route_member WHERE id IN
+ (SELECT id
+ FROM (SELECT id,
+ ROW_NUMBER() OVER (partition BY member, network, ref ORDER BY id) AS rnum
+ FROM osm_route_member) t
+ WHERE t.rnum > 1);
+CREATE UNIQUE INDEX IF NOT EXISTS osm_route_member_network_ref_idx ON osm_route_member ("member", "network", "ref");
+
CREATE INDEX IF NOT EXISTS osm_highway_linestring_osm_id_idx ON osm_highway_linestring ("osm_id");
CREATE UNIQUE INDEX IF NOT EXISTS osm_highway_linestring_gen_z11_osm_id_idx ON osm_highway_linestring_gen_z11 ("osm_id");
diff --git a/tests/import/500_import-highway.osm b/tests/import/500_import-highway.osm
index 7fcbec92..8b745512 100644
--- a/tests/import/500_import-highway.osm
+++ b/tests/import/500_import-highway.osm
@@ -147,4 +147,22 @@
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/tests/test-post-import.sql b/tests/test-post-import.sql
index f874a25a..b1af312c 100644
--- a/tests/test-post-import.sql
+++ b/tests/test-post-import.sql
@@ -160,6 +160,13 @@ BEGIN
INSERT INTO omt_test_failures VALUES(500, 'import', 'osm_transportation_name_linestring z12 route_rank expected 1, got ' || cnt);
END IF;
+ -- Duplicate route concurrencies collapsed
+ SELECT COUNT(*) INTO cnt FROM osm_route_member
+ WHERE network='US:I' AND ref='95';
+ IF cnt <> 1 THEN
+ INSERT INTO omt_test_failures VALUES(500, 'import', 'osm_route_member 1 route membership expected, got ' || cnt);
+ END IF;
+
-- Test 600
-- verify that atms are imported with correct name which can come from tags like operator or network