diff --git a/data/functions.sql b/data/functions.sql
index 2f46d0295..90d90ae00 100644
--- a/data/functions.sql
+++ b/data/functions.sql
@@ -83,24 +83,33 @@ BEGIN
 END;
 $$ LANGUAGE plpgsql IMMUTABLE;
 
--- mz_get_rel_network returns a network tag, or NULL, for a
--- given way ID.
+-- mz_get_rel_networks returns a list of triples of route type,
+-- network and ref tags, or NULL, for a given way ID.
 --
 -- it does this by joining onto the relations slim table, so it
 -- won't work if you dropped the slim tables, or didn't use slim
 -- mode in osm2pgsql.
 --
-CREATE OR REPLACE FUNCTION mz_get_rel_network(
+CREATE OR REPLACE FUNCTION mz_get_rel_networks(
   way_id bigint)
-RETURNS text AS $$
-BEGIN
-  RETURN mz_first_dedup(ARRAY(
-    SELECT mz_rel_get_tag(tags, 'network')
-    FROM planet_osm_rels
-    WHERE parts && ARRAY[way_id]
-      AND parts[way_off+1:rel_off] && ARRAY[way_id]));
-END;
-$$ LANGUAGE plpgsql STABLE;
+RETURNS text[] AS $$
+SELECT
+  array_agg(unnested)
+FROM (
+  SELECT
+    unnest(tags) AS unnested
+  FROM (
+    SELECT
+      hstore(tags)->ARRAY['route','network','ref'] AS tags
+    FROM
+      planet_osm_rels
+    WHERE
+      parts && ARRAY[way_id] AND
+      parts[way_off+1:rel_off] && ARRAY[way_id] AND
+      hstore(tags) ?& ARRAY['route','network','ref']
+    ) inner1
+  ) inner2;
+$$ LANGUAGE sql STABLE;
 
 -- adds the prefix onto every key in an hstore value
 CREATE OR REPLACE FUNCTION mz_hstore_add_prefix(
diff --git a/data/migrations/v1.0.0-cleanup.sql b/data/migrations/v1.0.0-cleanup.sql
new file mode 100644
index 000000000..3b1df1f4a
--- /dev/null
+++ b/data/migrations/v1.0.0-cleanup.sql
@@ -0,0 +1,2 @@
+-- drop no longer used single-network version of this function
+DROP FUNCTION mz_get_rel_network(bigint);
diff --git a/docs/layers.md b/docs/layers.md
index 8eab3e34d..d3de12ce3 100644
--- a/docs/layers.md
+++ b/docs/layers.md
@@ -837,13 +837,14 @@ To improve performance, some road segments are merged at low and mid-zooms. To f
 * `source`: `openstreetmap` or `naturalearthdata.com`
 * `kind`: one of High Road's values for `highway`, `major_road`, `minor_road`, `rail`, `path`, `ferry`, `piste`, `aerialway`, `aeroway`, `racetrack`, `portage_way` if `whitewater=portage_way`; or Natural Earth's `featurecla` value. You'll want to look at other tags like `highway` and `railway` for raw OpenStreetMap values. At low zooms, Natural Earth `featurecla` kinds of `Road` and `Ferry` are used. Look to `type` for more fidelity.
 * `landuse_kind`: See description above, values match values in the `landuse` layer.
-* `ref`: Used for road shields. Related, see `symbol` for pistes.
+* `ref`: Commonly-used reference for roads, for example "I 90" for Interstate 90. To use with shields, see the common optional properties `network` and `shield_text`. Related, see `symbol` for pistes.
 * `sort_key`: a suggestion for which order to draw features. The value is an integer where smaller numbers suggest that features should be "behind" features with larger numbers. At zooms >= 15, the `sort_key` is adjusted to realistically model bridge, tunnel, and layer ordering.
 
 #### Road properties (common optional):
 
 * `aerialway`: See kind list below.
 * `aeroway`: See kind list below.
+* `all_networks` and `all_shield_texts`: All the networks of which this road is a part, and all of the shield texts. See `network` and `shield_text` below. **Note** that these properties will not be present on MVT format tiles, as we cannot currently encode lists as values.
 * `bicycle_network`: Present if the feature is part of a cycling network. If so, the value will be one of `icn` for International Cycling Network, `ncn` for National Cycling Network, `rcn` for Regional Cycling Network, `lcn` for Local Cycling Network.
 * `cycleway`: `cycleway` tag from feature. If no `cycleway` tag is present but `cycleway:both` exists, we source from that tag instead.
 * `cycleway_left`: `cycleway_left` tag from feature
@@ -857,13 +858,14 @@ To improve performance, some road segments are merged at low and mid-zooms. To f
 * `is_tunnel`: `true` if the road is part of a tunnel. The property will not be present if the road is not part of a tunnel.
 * `leisure`: See kind list below.
 * `man_made`: See kind list below.
-* `network`: eg: `US:I` for the United States Interstate network, useful for shields and road selections.
+* `network`: eg: `US:I` for the United States Interstate network, useful for shields and road selections. This only contains _road_ network types. Please see `bicycle_network` and `walking_network` for bicycle and walking networks, respectively.
 * `oneway_bicycle`: `oneway:bicycle` tag from feature
 * `oneway`: `yes` or `no`
 * `piste_type`: See kind list below.
 * `railway`: the original OSM railway tag value
 * `segregated`: Set to `true` when a path allows both pedestrian and bicycle traffic, but when pedestrian traffic is segregated from bicycle traffic.
 * `service`: See value list below, provided for `railway` and `highway=service` roads.
+* `shield_text`: Contains text to display on a shield. For example, I 90 would have a `network` of `US:I` and a `shield_text` of `90`. The `ref`, `I 90`, is less useful for shield display without further processing.
 * `type`:  Natural Earth roads and ferry
 * `walking_network`: Present if the feature is part of a hiking network. If so, the value will be one of `iwn` for International Walking Network, `nwn` for National Walking Network, `rwn` for Regional Walking Network, `lwn` for Local Walking Network.
 * `kind_detail`: normalized values describing the kind value, see below.
diff --git a/integration-test/192-shield-text-ref.py b/integration-test/192-shield-text-ref.py
new file mode 100644
index 000000000..36211f455
--- /dev/null
+++ b/integration-test/192-shield-text-ref.py
@@ -0,0 +1,21 @@
+# US 101, "James Lick Freeway"
+# http://www.openstreetmap.org/way/27183379
+# http://www.openstreetmap.org/relation/108619
+assert_has_feature(
+    16, 10484, 25334, 'roads',
+    { 'kind': 'highway', 'network': 'US:US', 'id': 27183379,
+      'shield_text': '101' })
+
+# I-77, I-81, US-11 & US-52 all in one road West Virginia.
+#
+# http://www.openstreetmap.org/way/51388984
+# http://www.openstreetmap.org/relation/2309416
+# http://www.openstreetmap.org/relation/2301037
+# http://www.openstreetmap.org/relation/2297359
+# http://www.openstreetmap.org/relation/1027748
+assert_has_feature(
+    16, 18022, 25522, 'roads',
+    { 'kind': 'highway', 'network': 'US:I', 'id': 51388984,
+      'shield_text': '77',
+      'all_networks': ['US:I', 'US:I', 'US:US', 'US:US'],
+      'all_shield_texts': ['77', '81', '11', '52'] })
diff --git a/integration-test/358-merge-same-roads.py b/integration-test/358-merge-same-roads.py
index cde36249e..e5eb3123e 100644
--- a/integration-test/358-merge-same-roads.py
+++ b/integration-test/358-merge-same-roads.py
@@ -8,11 +8,21 @@
 # RAW QUERY: way(36.563,-122.377,37.732,-120.844)[highway=primary];>;
 # RAW QUERY: way(36.563,-122.377,37.732,-120.844)[highway=trunk];>;
 #
+
+def _freeze(thing):
+    if isinstance(thing, dict):
+        return frozenset([(_freeze(k), _freeze(v)) for k, v in thing.items()])
+
+    elif isinstance(thing, list):
+        return tuple([_freeze(i) for i in thing])
+
+    return thing
+
 with features_in_tile_layer(8, 41, 99, 'roads') as roads:
     features = set()
 
     for road in roads:
-        props = frozenset(road['properties'].items())
+        props = frozenset(_freeze(road['properties']))
         if props in features:
             raise Exception("Duplicate properties %r in roads layer, but "
                             "properties should be unique."
diff --git a/integration-test/647-cycle-route.py b/integration-test/647-cycle-route.py
index 4b81d139f..cc8fb7f31 100644
--- a/integration-test/647-cycle-route.py
+++ b/integration-test/647-cycle-route.py
@@ -3,17 +3,17 @@
 # http://www.openstreetmap.org/relation/32386
 assert_has_feature(
     16, 10487, 25327, 'roads',
-    { 'kind': 'major_road', 'cycleway': 'lane', 'network': 'lcn', 'bicycle_network': 'lcn' })
+    { 'kind': 'major_road', 'cycleway': 'lane', 'bicycle_network': 'lcn' })
 
 # Way: King Street (8920394) http://www.openstreetmap.org/way/8920394
 assert_has_feature(
     16, 10487, 25329, 'roads',
-    { 'kind': 'major_road', 'cycleway_left': 'lane', 'network': 'lcn', 'bicycle_network': 'lcn'})
+    { 'kind': 'major_road', 'cycleway_left': 'lane', 'bicycle_network': 'lcn'})
 
 # Way: King Street (397270776) http://www.openstreetmap.org/way/397270776
 assert_has_feature(
     16, 10487, 25329, 'roads',
-    { 'kind': 'major_road', 'cycleway_right': 'lane', 'network': 'lcn', 'bicycle_network': 'lcn'})
+    { 'kind': 'major_road', 'cycleway_right': 'lane', 'bicycle_network': 'lcn'})
 
 # Way: Clara-Immerwahr-Straße (287167007) http://www.openstreetmap.org/way/287167007
 assert_has_feature(
diff --git a/queries.yaml b/queries.yaml
index 19e6ac0c3..9a2149e5c 100644
--- a/queries.yaml
+++ b/queries.yaml
@@ -89,6 +89,7 @@ layers:
       - vectordatasource.transform.normalize_aerialways
       - vectordatasource.transform.normalize_cycleway
       - vectordatasource.transform.add_is_bicycle_related
+      - vectordatasource.transform.choose_most_important_network
       - vectordatasource.transform.road_trim_properties
       - vectordatasource.transform.remove_feature_id
       - vectordatasource.transform.tags_remove
@@ -567,7 +568,7 @@ post_process:
       source_layer: roads
       start_zoom: 0
       end_zoom: 14
-      properties: [name, ref, network]
+      properties: [name, ref, network, shield_text]
       where: >-
         (kind == 'rail' and zoom < 15) or
         (kind == 'minor_road' and zoom < 14) or
@@ -580,7 +581,7 @@ post_process:
       source_layer: roads
       start_zoom: 7
       end_zoom: 10
-      properties: [name, network]
+      properties: [name, network, shield_text]
       where: >-
         kind == 'major_road'
   # this is a patch to get rid of name, but keep ref & network, for highways
diff --git a/vectordatasource/transform.py b/vectordatasource/transform.py
index 04148dbea..714f29390 100644
--- a/vectordatasource/transform.py
+++ b/vectordatasource/transform.py
@@ -2764,6 +2764,34 @@ def add_uic_ref(shape, properties, fid, zoom):
         return shape, properties, fid
 
 
+def _freeze(thing):
+    """
+    Freezes something to a hashable item.
+    """
+
+    if isinstance(thing, dict):
+        return frozenset([(_freeze(k), _freeze(v)) for k, v in thing.items()])
+
+    elif isinstance(thing, list):
+        return tuple([_freeze(i) for i in thing])
+
+    return thing
+
+
+def _thaw(thing):
+    """
+    Reverse of the freeze operation.
+    """
+
+    if isinstance(thing, frozenset):
+        return dict([_thaw(i) for i in thing])
+
+    elif isinstance(thing, tuple):
+        return list([_thaw(i) for i in thing])
+
+    return thing
+
+
 def merge_features(ctx):
     """
     Merge (linear) features with the same properties together, attempting to
@@ -2814,7 +2842,7 @@ def merge_features(ctx):
 
         # because dicts are mutable and therefore not hashable, we have to
         # transform their items into a frozenset instead.
-        frozen_props = frozenset(props.items())
+        frozen_props = _freeze(props)
 
         if frozen_props in features_by_property:
             features_by_property[frozen_props][2].append(shape)
@@ -2833,7 +2861,7 @@ def merge_features(ctx):
         multi = MultiLineString(list_of_linestrings)
 
         # thaw the frozen properties to use in the new feature.
-        props = dict(frozen_props)
+        props = _thaw(frozen_props)
 
         # restore any 'id' property.
         if p_id is not None:
@@ -3676,3 +3704,69 @@ def normalize_operator_values(shape, properties, fid, zoom):
             return (shape, properties, fid)
 
     return (shape, properties, fid)
+
+
+def network_importance(route_type, network, ref):
+    """
+    Returns an integer representing the numeric importance of the network,
+    where lower numbers are more important.
+
+    This is to handle roads which are part of many networks, and ensuring
+    that the most important one is displayed. For example, in the USA many
+    roads can be part of both interstate (US:I) and "US" (US:US) highways,
+    and possibly state ones as well (e.g: US:NY:xxx). In addition, there
+    are international conventions around the use of "CC:national" and
+    "CC:regional:*" where "CC" is an ISO 2-letter country code.
+
+    Here we treat national-level roads as more important than regional or
+    lower, and assume that the deeper the network is in the hierarchy, the
+    less important the road. Roads with lower "ref" numbers are considered
+    more important than higher "ref" numbers, if they are part of the same
+    network.
+    """
+
+    if network == 'US:I' or ':national' in network:
+        network_code = 1
+    elif network == 'US:US' or ':regional' in network:
+        network_code = 2
+    else:
+        network_code = len(network.split(':')) + 3
+
+    try:
+        ref = max(int(ref), 0)
+    except ValueError:
+        ref = 0
+
+    return network_code * 10000 + min(ref, 9999)
+
+
+def choose_most_important_network(shape, properties, fid, zoom):
+    """
+    Use the `network_importance` function to select any road networks from
+    `mz_networks` and take the most important one.
+    """
+
+    networks = properties.pop('mz_networks', None)
+
+    if networks is not None:
+        # take the list and make triples out of it
+        itr = iter(networks)
+        triples = zip(itr, itr, itr)
+        triples = [t for t in triples if t[0] == 'road']
+
+        if len(triples) > 0:
+            def network_key(t):
+                return network_importance(*t)
+
+            networks = sorted(triples, key=network_key)
+
+            # expose first network as network/shield_text
+            route_type, network, ref = networks[0]
+            properties['network'] = network
+            properties['shield_text'] = ref
+
+            # expose all networks as well.
+            properties['all_networks'] = [n[1] for n in networks]
+            properties['all_shield_texts'] = [n[2] for n in networks]
+
+    return (shape, properties, fid)
diff --git a/yaml/roads.yaml b/yaml/roads.yaml
index 1715b9ffa..bd2ac8e39 100644
--- a/yaml/roads.yaml
+++ b/yaml/roads.yaml
@@ -51,7 +51,7 @@ global:
           CASE WHEN tags->'crossing' <> 'no' THEN tags->'crossing' END
       sidewalk: {col: tags->sidewalk}
   - &osm_network_from_relation
-      network: {expr: "mz_get_rel_network(osm_id)"}
+      mz_networks: {expr: "mz_get_rel_networks(osm_id)"}
   - &osm_network_from_tags
       network: {col: tags->network}
   - &osm_piste_properties