diff --git a/back-end/app.js b/back-end/app.js
index 02b662e..5b3a632 100644
--- a/back-end/app.js
+++ b/back-end/app.js
@@ -1,9 +1,42 @@
 // import and instantiate express
 const express = require('express'); // CommonJS import style!
 const app = express(); // instantiate an Express object
+require('dotenv').config();
 // we will put some server logic here later...
 
 const cors = require('cors');
+const { createGraph, findOptimalRoute } = require('./getOptimizedRoute.js');
 app.use(cors());
 
 module.exports = app;
+
+
+
+app.get('/getRoute', (req, res) => {
+    const busStops = {
+        unionsquare: [40.73498551788369, -73.990696048825],
+        tompkins: [40.7251277537963, -73.98121749968648],
+        hamilton: [40.720213039417494, -73.980207088181],
+        eastbroadway: [40.7141707879376, -73.9901227463216],
+        chinatown: [40.71559782189394, -73.99850504010124],
+        financial: [40.70811320415039, -74.00798229139403],
+        tribeca: [40.716765448621125, -74.00913568860388],
+        canal: [40.721857387647354, -74.00518353611693],
+        soho: [40.72488113646396, -74.00162848801607],
+        greenwich: [40.733368703161425, -74.00412600650982],
+        washingtonsquare: [40.731522867853634, -73.9971283464239],
+        jayst: [40.69225251854892, -73.98648974152808],
+        dumbo: [40.70372584858276, -73.98861865993923],
+        ikea: [40.672611811522145, -74.01009335210519]
+    }
+    const routes = {
+        route1: [busStops.washingtonsquare, busStops.unionsquare, busStops.tompkins, busStops.hamilton, busStops.eastbroadway, busStops.chinatown, busStops.financial, busStops.tribeca, busStops.canal, busStops.soho, busStops.greenwich, busStops.washingtonsquare],
+        route2: [busStops.jayst, busStops.dumbo, busStops.ikea],
+        route3: [busStops.jayst, busStops.eastbroadway, busStops.washingtonsquare, busStops.chinatown, busStops.financial],
+        route4: [busStops.eastbroadway, busStops.washingtonsquare, busStops.unionsquare, busStops.tompkins, busStops.hamilton, busStops.eastbroadway],
+    }
+    const graph = createGraph(routes);
+    let optimalRoute = findOptimalRoute(graph, req.query.origin, req.query.destination);
+    console.log(optimalRoute);
+    res.send('Hello World!'); 
+})
\ No newline at end of file
diff --git a/back-end/getOptimizedRoute.js b/back-end/getOptimizedRoute.js
new file mode 100644
index 0000000..c5b9dec
--- /dev/null
+++ b/back-end/getOptimizedRoute.js
@@ -0,0 +1,101 @@
+//this function creates a directed circular graph representation of of bus stops and the routes.
+/*in the output graph, the key represents a bus stop, and the value represents all the bus stops that 
+are directly reachavble from the key bus stop.*/
+function createGraph(routes) {
+    let graph = {};
+    for (let routeId in routes) {
+        let stops = routes[routeId];
+        for ( let i = 0; i < stops.length; i++) {
+            let currentStop = stops[i];
+            let nextStop = stops[(i + 1) % stops.length];
+            let currentKey = currentStop.toString();
+
+            if (!graph[currentKey]) {
+                graph[currentKey] = [];
+            }
+            graph[currentKey].push({ coordinates: nextStop, route: routeId });
+
+        }
+    }
+    return graph;
+}
+
+function getEuclideanDistance (origin, destination) {
+    let x1 = origin.split(',')[0];
+    let y1 = origin.split(',')[1];
+    let x2 = destination.split(',')[0];
+    let y2 = destination.split(',')[1];
+    return Math.sqrt(Math.pow((x2 - x1), 2) + Math.pow((y2 - y1), 2));
+}
+
+//find bus stops that are relatively close in term of walking distance
+function findAllReachableStops(graph, origin, threshold=0.013) {
+    let reachableStops = [];
+    for (busstop in graph){
+        busstop = busstop.toString();
+        let distance = getEuclideanDistance(busstop, origin);
+        if (distance < threshold) {
+            console.log('reachable stop found: '+graph[busstop][0].route);
+            reachableStops.push({coordinates: busstop, route: graph[busstop][0].route});
+        }
+    }
+
+    return reachableStops;
+
+}
+// return walking distance from point A to point B
+async function getWalkingDistance(origin, destination) {
+    origin = origin.split(',').join('%2C');
+    destination = destination.split(',').join('%2C');
+    let res = await fetch(`https://maps.googleapis.com/maps/api/distancematrix/json?units=imperial&origins=${origin}&destinations=${destination}&key=${process.env.EXPRESS_APP_MAP_API_KEY}`)
+    let data = await res.json();
+    res = data.rows[0].elements[0].duration.value;
+    return res;
+}
+
+function isOnSameRoute(stop1, stop2) {
+    console.log(stop1.route);
+    return stop1.route === stop2.route;
+}
+
+async function findOptimalRoute(graph, origin, destination) {
+    let minTotalDistance = Number.MAX_VALUE;
+    let optimalRoute = null;
+
+    // Find all reachable stops from origin and destination
+    let reachableFromOrigin = findAllReachableStops(graph, origin);
+    let reachableFromDestination = findAllReachableStops(graph, destination);
+
+    // Calculate route distances
+    for (let originStop of reachableFromOrigin) {
+        for (let destinationStop of reachableFromDestination) {
+            if (isOnSameRoute(originStop, destinationStop)) {
+                let distanceToOriginStop = await getWalkingDistance(origin, originStop.coordinates);
+                let distanceFromDestinationStop = await getWalkingDistance(destinationStop.coordinates, destination);
+
+                let totalDistance = distanceToOriginStop + distanceFromDestinationStop;
+                console.log('fetched from Google Maps API, total distance: '+totalDistance);
+                console.log('----------------------------------')
+                // Check if this route is better than the current best
+                if (totalDistance < minTotalDistance) {
+                    minTotalDistance = totalDistance;
+                    optimalRoute = { originStop, destinationStop };
+                }
+            }
+        }
+    }
+    console.log('optimal route: '+optimalRoute.originStop.route);
+    console.log('origin stop: '+optimalRoute.originStop.coordinates);
+    console.log('destination stop: '+optimalRoute.destinationStop.coordinates);
+
+    return optimalRoute;
+}
+
+module.exports = {
+    createGraph,
+    getEuclideanDistance,
+    findAllReachableStops,
+    getWalkingDistance,
+    isOnSameRoute,
+    findOptimalRoute
+}
\ No newline at end of file
diff --git a/front-end/src/utils/transportMarker.js b/front-end/src/utils/transportMarker.js
index 809c47e..52ffd00 100644
--- a/front-end/src/utils/transportMarker.js
+++ b/front-end/src/utils/transportMarker.js
@@ -20,7 +20,7 @@ export function updateTransportMarkers(transportData, markerRef, map) {
     const lat = parseFloat(transportInfo.latitude);
     const lng = parseFloat(transportInfo.longitude);
     const newPosition = new window.google.maps.LatLng(lat, lng);
-    const iconUpdate = marker && marker.direction !== transportInfo.calculatedCourse;
+    const iconUpdate = marker && (marker.direction !== transportInfo.calculatedCourse || transportInfo.route  === 'Ferry Route');
 
     if (marker) {
       // Update the position of the existing marker
@@ -29,12 +29,12 @@ export function updateTransportMarkers(transportData, markerRef, map) {
 
       // Update the icon of the existing marker
       if (iconUpdate) {
-        const newIcon = generateTransportMarkerIcon(transportInfo.color, transportInfo.calculatedCourse);
+        const newIcon = generateTransportMarkerIcon(transportInfo.color, transportInfo.calculatedCourse, transportInfo.route);
         marker.setIcon(newIcon);
       }
     } else {
       // Create a new marker
-      const newIcon = generateTransportMarkerIcon(transportInfo.color, transportInfo.calculatedCourse);
+      const newIcon = generateTransportMarkerIcon(transportInfo.color, transportInfo.calculatedCourse, transportInfo.route);
       let transportMarker = createTransportMarker(newPosition, transportInfo, map, newIcon);
       markerRef.current[transport] = transportMarker;
     }
@@ -46,11 +46,11 @@ function createTransportMarker(position, transportInfo, map) {
     position,
     map,
     title: String(transportInfo.busId),
-    icon: generateTransportMarkerIcon(transportInfo.color || '#000', transportInfo.calculatedCourse || 0),
+    icon: generateTransportMarkerIcon(transportInfo.color || '#000', transportInfo.calculatedCourse || 0, transportInfo.route || 0),
   });
 
   let infowindow = new window.google.maps.InfoWindow({
-    content: `<div><strong>No.${transportInfo.busId}</strong><br>Line: ${transportInfo.route}</div>`,
+    content: `<div><strong>No.${transportInfo.busId}</strong><br>Line: ${transportInfo.route}</div>Passenger Count: ${transportInfo.paxLoad}</div>`,
   });
 
   transportMarker.direction = transportInfo.calculatedCourse;
@@ -108,7 +108,7 @@ function animateMarker(marker, startPosition, endPosition, duration) {
 
 // Generate custom transport marker icon (currently only support buses)
 // Original source of bus svg path: www.svgrepo.com
-function generateTransportMarkerIcon(color, direction) {
+function generateTransportMarkerIcon(color, direction, route) {
   const svg = `<?xml version="1.0" encoding="utf-8"?>
   <svg width="24" height="24" xmlns="http://www.w3.org/2000/svg">
     <g class="layer" transform="rotate(${direction}, 12, 12)">
@@ -122,9 +122,15 @@ function generateTransportMarkerIcon(color, direction) {
       </g>
     </g>
   </svg>`;
+  let iconImg = 'data:image/svg+xml;charset=UTF-8;base64,' + btoa(svg);
+  let scaledSize = new window.google.maps.Size(40, 40);
+  if (route === 'Ferry Route') {
+    iconImg = 'busIcons/busIcon_routeFerry_Route.png';
+    scaledSize= new window.google.maps.Size(30, 30);
+  }
   const icon = {
-    url: 'data:image/svg+xml;charset=UTF-8;base64,' + btoa(svg),
-    scaledSize: new window.google.maps.Size(40, 40),
+    url: iconImg,
+    scaledSize: scaledSize,
   };
   return icon;
 }