diff --git a/api/obs/api/routes/tiles.py b/api/obs/api/routes/tiles.py
index 35e1d95..7d843b2 100644
--- a/api/obs/api/routes/tiles.py
+++ b/api/obs/api/routes/tiles.py
@@ -39,10 +39,12 @@ async def tiles(req, zoom: int, x: int, y: str):
         tile = get_tile(req.app.config.TILES_FILE, int(zoom), int(x), int(y))
 
     else:
-        user_id = req.ctx.get_single_arg("user_id", convert=int, default=None)
-        if user_id is not None:
-            if req.ctx.user is None or req.ctx.user.id != user_id:
+        user_id = None
+        username = req.ctx.get_single_arg("user", default=None)
+        if username is not None:
+            if req.ctx.user is None or req.ctx.user.username != username:
                 raise Forbidden()
+            user_id = req.ctx.user.id
 
         tile = await req.ctx.db.scalar(
             text(
diff --git a/api/tools/prepare_sql_tiles.py b/api/tools/prepare_sql_tiles.py
index 90100e6..d8ab5bb 100755
--- a/api/tools/prepare_sql_tiles.py
+++ b/api/tools/prepare_sql_tiles.py
@@ -48,7 +48,7 @@ DROP FUNCTION IF EXISTS {fname}(integer, integer, integer{extra_args_types});
 CREATE FUNCTION {fname}(zoom integer, x integer, y integer{extra_args_definitions})
 RETURNS {'TABLE(mvt bytea, key text)' if self.key_column else 'bytea'} AS $$
 {self.generate_sql()};
-$$ LANGUAGE SQL STABLE RETURNS NULL ON NULL INPUT;"""
+$$ LANGUAGE SQL STABLE CALLED ON NULL INPUT;"""
 
 
 def parse_pg_url(url=app.config.POSTGRES_URL):
diff --git a/tile-generator/layers/obs_roads/layer.sql b/tile-generator/layers/obs_roads/layer.sql
index 53d8dd3..4521a66 100644
--- a/tile-generator/layers/obs_roads/layer.sql
+++ b/tile-generator/layers/obs_roads/layer.sql
@@ -1,6 +1,7 @@
 DROP FUNCTION IF EXISTS layer_obs_roads(geometry, int);
+DROP FUNCTION IF EXISTS layer_obs_roads(geometry, int, integer, timestamp, timestamp);
 
-CREATE OR REPLACE FUNCTION layer_obs_roads(bbox geometry, zoom_level int)
+CREATE OR REPLACE FUNCTION layer_obs_roads(bbox geometry, zoom_level int, user_id integer, min_time timestamp, max_time timestamp)
 RETURNS TABLE(
   way_id bigint,
   geometry geometry,
@@ -25,16 +26,24 @@ RETURNS TABLE(
       PERCENTILE_CONT(0.5) WITHIN GROUP (ORDER BY distance_overtaker) as distance_overtaker_median,
       array_agg(distance_overtaker) as distance_overtaker_array,
       count(overtaking_event.id)::int as distance_overtaker_count,
-      (select count(id) from road_usage where road_usage.way_id = road.way_id and
-          (road.directionality != 0 or road_usage.direction_reversed = r.rev)) as usage_count,
+      (
+        SELECT count(road_usage.id) from road_usage
+        JOIN track ON track.id = road_usage.track_id
+        WHERE road_usage.way_id = road.way_id
+          AND (road.directionality != 0 or road_usage.direction_reversed = r.rev)
+          AND (user_id is NULL or user_id = track.author_id)
+          AND road_usage.time BETWEEN COALESCE(min_time, '1900-01-01'::timestamp) AND COALESCE(max_time, '2100-01-01'::timestamp)
+      ) as usage_count,
       r.dir as direction,
       road.zone::zone_type as zone,
       case when road.directionality = 0 then r.dir else 0 end as offset_direction
     FROM road
     LEFT JOIN (VALUES (-1, TRUE), (1, FALSE), (0, FALSE)) AS r(dir, rev) ON (abs(r.dir) != road.directionality)
     FULL OUTER JOIN overtaking_event ON (road.way_id = overtaking_event.way_id and (road.directionality != 0 or overtaking_event.direction_reversed = r.rev))
-    -- WHERE road.name = 'Merzhauser Straße'
+      JOIN track ON overtaking_event.track_id = track.id
     WHERE road.geometry && bbox
-    GROUP BY road.name, road.way_id, road.geometry, road.directionality, r.dir, r.rev, road.zone;
+      AND (user_id is NULL or user_id = track.author_id)
+      AND overtaking_event.time BETWEEN COALESCE(min_time, '1900-01-01'::timestamp) AND COALESCE(max_time, '2100-01-01'::timestamp)
+    GROUP BY road.name, road.way_id, road.geometry, road.directionality, road.zone, r.dir, r.rev;
 
 $$ LANGUAGE SQL IMMUTABLE;
diff --git a/tile-generator/layers/obs_roads/obs_roads.yaml b/tile-generator/layers/obs_roads/obs_roads.yaml
index 3b0e918..2f1f926 100644
--- a/tile-generator/layers/obs_roads/obs_roads.yaml
+++ b/tile-generator/layers/obs_roads/obs_roads.yaml
@@ -48,7 +48,7 @@ layer:
           direction,
           zone,
           offset_direction
-        FROM layer_obs_roads(!bbox!, z(!scale_denominator!))
+        FROM layer_obs_roads(!bbox!, z(!scale_denominator!), user_id, min_time, max_time)
       ) AS t
 
 schema: