Edit in JSFiddle

function initialize() {
    var myLatlng = new google.maps.LatLng(51.24343506423872,22.56488800048828);
    var styles = [{
            featureType: "road",
            stylers: [
                { lightness: 10 }, // * Jasność.
                { saturation: -100 } // * Nasycenie.
                ]
        }, {
            featureType: "road.local",
            elementType: "geometry.fill",
            stylers: [
                { hue: "#ff9900" },
                // { saturation: 100 },
                // { lightness: 100 },
                { gamma: 1 },
                { weight: 7 }
                // { color: "#00ff00" },
                // { inverse_lightness: true }
            ]
        }
    ];

    var mapOptions = {
      zoom: 11,
      center: myLatlng,
      mapTypeId: google.maps.MapTypeId.ROADMAP
    }
    
    var map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions);
    map.setOptions({styles: styles});
}
    
google.maps.event.addDomListener(window, 'load', initialize);

<script src='https://maps.googleapis.com/maps/api/js?v=3.exp&sensor=false'> </script>
<div id="map-canvas"></div>

#map-canvas{
    height: 400px;
    width: 400px;
}