diff --git a/db/migrations/20260601000019_fn_vehicle_trips.sql b/db/migrations/20260601000019_fn_vehicle_trips.sql
index 34b1c25..2a7eac9 100644
--- a/db/migrations/20260601000019_fn_vehicle_trips.sql
+++ b/db/migrations/20260601000019_fn_vehicle_trips.sql
@@ -33,8 +33,13 @@
 -- Falls back to movement-only segmentation (has_acc_data=false in the
 -- response) when every position for the day has acc_state IS NULL.
 
+-- Drop any prior signature; the function identity is (name + arg types),
+-- so a CREATE OR REPLACE with a different arg type would create a sibling.
+DROP FUNCTION IF EXISTS serve.fn_vehicle_trips(integer, date);
+DROP FUNCTION IF EXISTS serve.fn_vehicle_trips(bigint, date);
+
 CREATE OR REPLACE FUNCTION serve.fn_vehicle_trips(
-    p_vehicle_id integer,
+    p_vehicle_id bigint,
     p_date_eat   date
 ) RETURNS jsonb
 LANGUAGE plpgsql STABLE
@@ -385,4 +390,5 @@ $fn$;
 
 -- migrate:down
 
+DROP FUNCTION IF EXISTS serve.fn_vehicle_trips(bigint, date);
 DROP FUNCTION IF EXISTS serve.fn_vehicle_trips(integer, date);