diff --git a/apps/server/src/lane-status.ts b/apps/server/src/lane-status.ts
index 746ad3e..1d26585 100644
--- a/apps/server/src/lane-status.ts
+++ b/apps/server/src/lane-status.ts
@@ -15,12 +15,15 @@ import { directionOf } from "./device-resolve.js";
 
 /** How long after the last vehicle detection a lane stays "busy" before clearing.
  *  Must exceed the camera's `active` re-fire interval so a still-present car keeps the
- *  lane busy. Measured on the test unit: while a vehicle is in the zone the camera
- *  re-fires `active` about every ~1s — so a few seconds of silence reliably means the
- *  car has left. 5s gives fast clearing without flicker. Override with LANE_BUSY_TTL_MS. */
+ *  lane busy. MEASURED on the test unit (controlled in/out test): the re-fire rate is
+ *  MOVEMENT-driven, not a fixed rate — ~1-3s apart while the car moves, but stretching
+ *  to ~15-25s when it sits MOTIONLESS in the zone. So the TTL must clear the still-car
+ *  gap (~25s) or a parked car flickers free. The camera has ~no dwell lag (it goes
+ *  silent within a second of the car leaving), so 30s clears promptly after departure
+ *  while keeping a motionless car solidly busy. Override with LANE_BUSY_TTL_MS. */
 export function busyTtlMs(): number {
-  const raw = Number(process.env.LANE_BUSY_TTL_MS ?? 5_000);
-  return Number.isFinite(raw) && raw > 0 ? raw : 5_000;
+  const raw = Number(process.env.LANE_BUSY_TTL_MS ?? 30_000);
+  return Number.isFinite(raw) && raw > 0 ? raw : 30_000;
 }
 
 export class LaneStatus {