Create multiple routes in a map

multiple-route-map.js

var location1 = new google.maps.LatLng(34.04429454929703, -118.22793351693724);
      var location2 = new google.maps.LatLng(33.688522885631706, -116.15151750131224);

      var location3 = new google.maps.LatLng(32.69561555501597, -117.06338273568724);
      var location4 = new google.maps.LatLng(34.525395303965354, -117.27212297006224);

      var map;
      var mapOptions = { center: new google.maps.LatLng(42.5584308, -70.8597732), zoom: 3,
        mapTypeId: google.maps.MapTypeId.ROADMAP };

      function initialize() {
        map = new google.maps.Map(document.getElementById("map_canvas"), mapOptions);
        directionsService = new google.maps.DirectionsService();
        directionsDisplay = new google.maps.DirectionsRenderer({
          suppressMarkers: false,
          suppressInfoWindows: true
        });
        directionsDisplay.setMap(map);

        var request = {
          origin: location1, 
          destination: location2,
          travelMode: google.maps.DirectionsTravelMode.DRIVING
        };
        directionsService.route(request, function(response, status) {
          if (status == google.maps.DirectionsStatus.OK) {
            directionsDisplay.setDirections(response);
          }
        });


        //directionsService = new google.maps.DirectionsService();
        directionsDisplay2 = new google.maps.DirectionsRenderer({
          suppressMarkers: false,
          suppressInfoWindows: true
        });
        directionsDisplay2.setMap(map);

        var request = {
          origin: location3, 
          destination: location4,
          travelMode: google.maps.DirectionsTravelMode.DRIVING
        };
        directionsService.route(request, function(response, status) {
          if (status == google.maps.DirectionsStatus.OK) {
            directionsDisplay2.setDirections(response);
          }
        });
      }
      google.maps.event.addDomListener(window, 'load', initialize);