diff --git a/.env.example b/.env.example
index 9898a63..7f6e340 100644
--- a/.env.example
+++ b/.env.example
@@ -3,4 +3,4 @@ ADMIN_TOKEN=
 ADMIN_AUTH_REQUIRED=false
 KAKAO_JAVASCRIPT_KEY=07f4728599ceaf4299f77c772a135423
 SIMULATOR_ENABLED=true
-SIMULATOR_INTERVAL_MS=4000
+SIMULATOR_INTERVAL_MS=1000
diff --git a/.env.nas.example b/.env.nas.example
index d04ea7d..6c69cec 100644
--- a/.env.nas.example
+++ b/.env.nas.example
@@ -3,4 +3,4 @@ ADMIN_TOKEN=change_this_admin_token
 ADMIN_AUTH_REQUIRED=false
 KAKAO_JAVASCRIPT_KEY=07f4728599ceaf4299f77c772a135423
 SIMULATOR_ENABLED=true
-SIMULATOR_INTERVAL_MS=4000
+SIMULATOR_INTERVAL_MS=1000
diff --git a/README.md b/README.md
index ba49e24..ac11da3 100644
--- a/README.md
+++ b/README.md
@@ -56,7 +56,8 @@ behind Synology Reverse Proxy.
 
 During early testing, keep `SIMULATOR_ENABLED=true` to show moving demo
 vehicles without Android phones. The simulator publishes fresh locations every
-`SIMULATOR_INTERVAL_MS` milliseconds.
+`SIMULATOR_INTERVAL_MS` milliseconds. The web map interpolates between fresh
+positions so vehicles move smoothly instead of jumping between points.
 
 ## Maintenance Scripts
 
diff --git a/apps/server/src/server.js b/apps/server/src/server.js
index a64edf2..f7efbd2 100644
--- a/apps/server/src/server.js
+++ b/apps/server/src/server.js
@@ -12,7 +12,7 @@ const ADMIN_TOKEN = process.env.ADMIN_TOKEN || "";
 const ADMIN_AUTH_REQUIRED = parseBoolean(process.env.ADMIN_AUTH_REQUIRED, false);
 const DEFAULT_KAKAO_JAVASCRIPT_KEY = "07f4728599ceaf4299f77c772a135423";
 const SIMULATOR_ENABLED = parseBoolean(process.env.SIMULATOR_ENABLED, true);
-const SIMULATOR_INTERVAL_MS = clampNumber(Number(process.env.SIMULATOR_INTERVAL_MS || 4000), 1000, 60000);
+const SIMULATOR_INTERVAL_MS = clampNumber(Number(process.env.SIMULATOR_INTERVAL_MS || 1000), 1000, 60000);
 const SIMULATOR_HISTORY_EVERY = clampNumber(Number(process.env.SIMULATOR_HISTORY_EVERY || 3), 1, 30);
 
 const DRIVERS_FILE = path.join(DATA_DIR, "drivers.json");
diff --git a/apps/web/public/app.js b/apps/web/public/app.js
index 21aae5d..9a8feb4 100644
--- a/apps/web/public/app.js
+++ b/apps/web/public/app.js
@@ -5,6 +5,7 @@ const state = {
   infoOverlay: null,
   routeOverlay: null,
   routeDestinationOverlay: null,
+  markerAnimationMs: 900,
   drivers: new Map(),
   locations: new Map(),
   selectedDriverId: "",
@@ -652,7 +653,8 @@ function updateMarker(location) {
 }
 
 function updateKakaoMarker(location) {
-  const position = new kakao.maps.LatLng(location.latitude, location.longitude);
+  const targetPosition = createPosition(location.latitude, location.longitude);
+  const kakaoPosition = new kakao.maps.LatLng(targetPosition.latitude, targetPosition.longitude);
   const status = getLocationStatus(location);
   const markerElement = createTruckMarkerElement(location, status);
 
@@ -662,23 +664,25 @@ function updateKakaoMarker(location) {
     marker = {
       provider: "kakao",
       overlay: new kakao.maps.CustomOverlay({
-        position,
+        position: kakaoPosition,
         content: markerElement,
         yAnchor: 1
-      })
+      }),
+      currentPosition: targetPosition
     };
     marker.overlay.setMap(state.map);
     state.markers.set(location.driverId, marker);
   } else {
-    marker.overlay.setPosition(position);
     marker.overlay.setContent(markerElement);
+    animateMarkerPosition(marker, targetPosition);
   }
 }
 
 function updateLeafletMarker(location) {
   const status = getLocationStatus(location);
   const vehicleType = getVehicleType(location);
-  const position = [location.latitude, location.longitude];
+  const targetPosition = createPosition(location.latitude, location.longitude);
+  const leafletPosition = [targetPosition.latitude, targetPosition.longitude];
   const icon = L.divIcon({
     className: `leaflet-truck-marker truck-marker ${status.key} ${vehicleType.className}`,
     html: createTruckMarkerHtml(location, vehicleType),
@@ -692,16 +696,17 @@ function updateLeafletMarker(location) {
   if (!marker) {
     marker = {
       provider: "leaflet",
-      marker: L.marker(position, { icon, title: location.vehicleNo || location.driverId })
+      marker: L.marker(leafletPosition, { icon, title: location.vehicleNo || location.driverId }),
+      currentPosition: targetPosition
     };
     marker.marker.on("click", () => focusLocation(location));
     marker.marker.addTo(state.map);
     state.markers.set(location.driverId, marker);
   } else {
-    marker.marker.setLatLng(position);
     marker.marker.setIcon(icon);
     marker.marker.off("click");
     marker.marker.on("click", () => focusLocation(location));
+    animateMarkerPosition(marker, targetPosition);
   }
 }
 
@@ -728,7 +733,85 @@ function createTruckMarkerHtml(location, vehicleType = getVehicleType(location))
   `;
 }
 
+function animateMarkerPosition(marker, targetPosition) {
+  const fromPosition = marker.currentPosition || getMarkerPosition(marker) || targetPosition;
+
+  if (calculateDistanceKm(fromPosition, targetPosition) < 0.01) {
+    setMarkerPosition(marker, targetPosition);
+    marker.currentPosition = targetPosition;
+    return;
+  }
+
+  cancelMarkerAnimation(marker);
+
+  const startedAt = window.performance.now();
+  const duration = state.markerAnimationMs;
+
+  const tick = (timestamp) => {
+    const progress = Math.min(1, (timestamp - startedAt) / duration);
+    const easedProgress = easeInOutCubic(progress);
+    const nextPosition = {
+      latitude: interpolateNumber(fromPosition.latitude, targetPosition.latitude, easedProgress),
+      longitude: interpolateNumber(fromPosition.longitude, targetPosition.longitude, easedProgress)
+    };
+
+    setMarkerPosition(marker, nextPosition);
+    marker.currentPosition = nextPosition;
+
+    if (progress < 1) {
+      marker.animationFrame = window.requestAnimationFrame(tick);
+    } else {
+      marker.animationFrame = null;
+      marker.currentPosition = targetPosition;
+      setMarkerPosition(marker, targetPosition);
+    }
+  };
+
+  marker.animationFrame = window.requestAnimationFrame(tick);
+}
+
+function cancelMarkerAnimation(marker) {
+  if (!marker?.animationFrame) return;
+  window.cancelAnimationFrame(marker.animationFrame);
+  marker.animationFrame = null;
+}
+
+function getMarkerPosition(marker) {
+  if (marker.provider === "leaflet" && marker.marker?.getLatLng) {
+    const position = marker.marker.getLatLng();
+    return createPosition(position.lat, position.lng);
+  }
+
+  return marker.currentPosition || null;
+}
+
+function setMarkerPosition(marker, position) {
+  if (marker.provider === "kakao") {
+    marker.overlay.setPosition(new kakao.maps.LatLng(position.latitude, position.longitude));
+    return;
+  }
+
+  if (marker.provider === "leaflet") {
+    marker.marker.setLatLng([position.latitude, position.longitude]);
+  }
+}
+
+function createPosition(latitude, longitude) {
+  return {
+    latitude: Number(latitude),
+    longitude: Number(longitude)
+  };
+}
+
+function easeInOutCubic(value) {
+  return value < 0.5
+    ? 4 * value * value * value
+    : 1 - ((-2 * value + 2) ** 3) / 2;
+}
+
 function removeMarker(marker) {
+  cancelMarkerAnimation(marker);
+
   if (marker.provider === "kakao") {
     marker.overlay.setMap(null);
     return;